[ASH] Ensure identity-shared package name works with startActivityForResult

The package name obtained from identity sharing API on U+ was not
picked up due to a bug in LaunchIntentDispatcher not setting it if
CCT was launched vis startActivityForResult. This CL fixes it.
Now Activity#launchedFromPackage() is always passed through
the extra IntentHandler#IntentHandler.EXTRA_LAUNCHED_FROM_PACKAGE
regardless of launch methods (startActivity/startActivityForResult).

Bug: 332592694
Change-Id: Ie35f427d7ec93ba61d7159f88e01147d929bfb42
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5426510
Reviewed-by: Michael Thiessen <mthiesse@chromium.org>
Commit-Queue: Jinsuk Kim <jinsukkim@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1282731}