Handle cross profile error in backlinks

- While sending screenshots of cross profile apps to note-taking apps is
  fine, sending deeplinks doesn't work as the note-taking app will not
  be able to open the backlink in the other profile. So, don't backlink
  if the screenshotted app is not of same user and show an error msg to
  user.
- Also, updated the ViewModel to inject application context to retrieve
  PackageManager from appropriate user's context instead of injecting
  and using current user's PackageManager.

Bug: 356513124
Test: atest AppClipsActivityTest AppClipsViewModelTest
Flag: com.android.systemui.app_clips_backlinks
Change-Id: Ifad8d58212c82b0dae13ca881ff187f449a085aa