Reland "[Sharesheet] Refactor Sharesheet to map actions by const, not UI string"

This is a reland of commit 434c4df1

Failure reason: MSAN failed for using active_share_action_type_ while
uninitialized in the *SharesheetBubbleView* tests.

Original change's description:
> [Sharesheet] Refactor Sharesheet to map actions by const, not UI string
>
> Refactors the Sharesheet Cache and related classes to use const enum
> ShareTypes to distinguish Sharesheet actions, rather than the user
> visible strings.
>
> Clipboard & Quick Share from Files, and Copy to Clipboard, Quick Share,
> and send to Files from Photos App (Arc++).
>
> Bug: b:326633226
> Test: Unit tests, tested that I could manually perform Copy to
> Change-Id: If0ddb1410322aad1d8f4439f775ebe1c1b1166b4
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5321767


> Reviewed-by: Dominick Ng <dominickn@chromium.org>
> Commit-Queue: Daniel Classon <dclasson@google.com>
> Cr-Commit-Position: refs/heads/main@{#1280233}

Bug: b:326633226
Test: Locally ran MSAN unit_tests and browser_tests.
Change-Id: I7f160033c9bc1bf02db4be022680d2e8430d5d71
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5408136


Commit-Queue: Daniel Classon <dclasson@google.com>
Reviewed-by: Dominick Ng <dominickn@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1280922}