Merge changes from topics "compose_bigtextstyle", "compose_header_only",...

Merge changes from topics "compose_bigtextstyle", "compose_header_only", "compose_largeicon", "create_compose_notifs_pod" into main

* changes:
  [Compose Notifs] Center title & expander when we have no content
  [Compose Notifs] Support large icon
  [Compose Notifs] Allow longer text when expanded
  Create pod for Compose Notifs