Implement Bundle Header in Compose

First compose version of BundleHeader that will be used inside of a
ComposeView within `NotificationChildrenContainer`.

Test: Manual tests in Gallery app, as well as screenshot test added for
all current variants.
Flag: com.android.systemui.notification_bundle_ui
Bug: b/389839492 b/394476643 b/394476670 b/394478037 b/394478046

Change-Id: Ibaf1ddff3d1224f6d31e9cef663a6fdbcb2b1ce2