#614 - Consistent message ID & FlaggableElement fix

[Klotske]

Might close #614.

Introduced consistent ID's; Changed typings to include frontend_message_id.
Included message type in props, separated props from function definitions.

Changed FlaggableElement component & /api/set_label api route to fix report sending.

Fixed Chakra error in MessageTableEntry component (LinkOverlay is redundant).

[fozziethebeat]

There's probably a little more cleanup to the message issue left but this is 90% of what we needed

[fozziethebeat]

Merging, this hasn't incorporated the end2end test fixes so the failure is expected