fix(menu-item): Improve keyboard navigability when href populated (#8408)

**Related Issue:** #8135 

## Summary

Author: macandcheese

packages/calcite-components/src/components/menu-item/menu-item.e2e.ts

@@ -50,6 +50,39 @@ describe("calcite-menu-item", () => {
     expect(eventSpy).toHaveReceivedEventTimes(1);
   });
 
+  describe("href support", () => {
+    const testHref = "#nature";
+    const testEl = `<calcite-menu><calcite-menu-item id="Nature" text="Nature" href="${testHref}"></calcite-menu-item></calcite-menu>`;
+
+    it("should navigate to a new url when href provided and user interacts with click", async () => {
+      const page = await newE2EPage();
+      await page.setContent(html`${testEl}`);
+      const originalUrl = page.url();
+      await page.waitForChanges();
+
+      const menuItem = await page.find("calcite-menu-item");
+      await page.waitForChanges();
+      await menuItem.click();
+      await page.waitForChanges();
+      const newUrl = page.url();
+      expect(newUrl).toEqual(originalUrl + testHref);
+    });
+
+    it("should navigate to a new url when href provided and user interacts with `enter` key", async () => {
+      const page = await newE2EPage();
+      await page.setContent(html`${testEl}`);
+      const originalUrl = page.url();
+      await page.waitForChanges();
+
+      await page.keyboard.press("Tab");
+      await page.waitForChanges();
+      await page.keyboard.press("Enter");
+      await page.waitForChanges();
+      const newUrl = page.url();
+      expect(newUrl).toEqual(originalUrl + testHref);
+    });
+  });
+
   it("should emit calciteMenuItemSelect event when user select the text area of the component using Enter or Space key", async () => {
     const page = await newE2EPage();
     await page.setContent(html`

packages/calcite-components/src/components/menu-item/menu-item.tsx

@@ -266,61 +266,54 @@ export class CalciteMenuItem implements LoadableComponent, T9nComponent, Localiz
   };
 
   private keyDownHandler = async (event: KeyboardEvent): Promise<void> => {
-    // opening and closing of submenu is handled here. Any other functionality is bubbled to parent menu.
-    if (event.key === " " || event.key === "Enter") {
-      this.selectMenuItem(event);
-      if (
-        this.hasSubmenu &&
-        (!this.href || (this.href && event.target === this.dropdownActionEl))
-      ) {
-        this.open = !this.open;
+    const { hasSubmenu, href, layout, open, submenuItems } = this;
+    const key = event.key;
+    const targetIsDropdown = event.target === this.dropdownActionEl;
+    if (key === " " || key === "Enter") {
+      if (hasSubmenu && (!href || (href && targetIsDropdown))) {
+        this.open = !open;
       }
-      event.preventDefault();
-    } else if (event.key === "Escape") {
-      if (this.open) {
+      if (!(href && targetIsDropdown) && key !== "Enter") {
+        this.selectMenuItem(event);
+      }
+      if (key === " " || (href && targetIsDropdown)) {
+        event.preventDefault();
+      }
+    } else if (key === "Escape") {
+      if (open) {
         this.open = false;
         return;
       }
       this.calciteInternalMenuItemKeyEvent.emit({ event });
       event.preventDefault();
-    } else if (event.key === "ArrowDown" || event.key === "ArrowUp") {
+    } else if (key === "ArrowDown" || key === "ArrowUp") {
       event.preventDefault();
-      if (
-        (event.target === this.dropdownActionEl || !this.href) &&
-        this.hasSubmenu &&
-        !this.open &&
-        this.layout === "horizontal"
-      ) {
+      if ((targetIsDropdown || !href) && hasSubmenu && !open && layout === "horizontal") {
         this.open = true;
         return;
       }
       this.calciteInternalMenuItemKeyEvent.emit({
         event,
-        children: this.submenuItems,
-        isSubmenuOpen: this.open && this.hasSubmenu,
+        children: submenuItems,
+        isSubmenuOpen: open && hasSubmenu,
       });
-    } else if (event.key === "ArrowLeft") {
+    } else if (key === "ArrowLeft") {
       event.preventDefault();
       this.calciteInternalMenuItemKeyEvent.emit({
         event,
-        children: this.submenuItems,
+        children: submenuItems,
         isSubmenuOpen: true,
       });
-    } else if (event.key === "ArrowRight") {
+    } else if (key === "ArrowRight") {
       event.preventDefault();
-      if (
-        (event.target === this.dropdownActionEl || !this.href) &&
-        this.hasSubmenu &&
-        !this.open &&
-        this.layout === "vertical"
-      ) {
+      if ((targetIsDropdown || !href) && hasSubmenu && !open && layout === "vertical") {
         this.open = true;
         return;
       }
       this.calciteInternalMenuItemKeyEvent.emit({
         event,
-        children: this.submenuItems,
-        isSubmenuOpen: this.open && this.hasSubmenu,
+        children: submenuItems,
+        isSubmenuOpen: open && hasSubmenu,
       });
     }
   };

packages/calcite-components/src/demos/menu.html

@@ -440,4 +440,11 @@ <h3>
       <calcite-panel heading="Example"><calcite-block heading="Content" open></calcite-block></calcite-panel>
     </calcite-shell>
   </body>
+  <script>
+    document.querySelectorAll("calcite-menu-item").forEach((item) => {
+      item.addEventListener("calciteMenuItemSelect", (event) => {
+        console.log(event);
+      });
+    });
+  </script>
 </html>