Add missing -e flag when preparing PyPI constraints (apache#47445)

When preparing `PyPI` constraints we are using `all-core` extra
to install all core dependencies of Airflow + all providers that
are downloaded from `PyPI`. However `all-core` extra is only available
in editable installation, not in standard one, so we need to use
editable installation to make use of the extra.

scripts/in_container/run_generate_constraints.py

@@ -423,6 +423,7 @@ def generate_constraints_pypi_providers(config_params: ConfigParams) -> None:
         run_command(
             cmd=[
                 *config_params.get_install_command,
+                "-e",
                 ".[all-core]",
                 "--reinstall",  # We need to pull the provider packages from PyPI - not use the local ones
                 *packages_to_install,