Preserve bubbles when cancelling notifications.

[scueZ]

Contributor checklist

• I am following the Code Style Guidelines
• I have tested my contribution on these devices:

• Samsung Galaxy S23, Android 15

• My contribution is fully baked and ready to be merged as is
• I ensure that all the open issues my contribution fixes are mentioned in the commit message of my first commit using the Fixes #1234 syntax

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Description

Fixes #14699.

When Signal cancels message notifications — for example after messages are read on a linked device — NotificationManager.cancel() also dismisses any bubble attached to the notification. For users who keep conversations bubbled, reading on another device therefore destroys their bubbles, whereas the system's swipe-dismiss gesture hides the notification but keeps the bubble.

This change re-posts collapsed bubble notifications with BubbleMetadata.setSuppressNotification(true) instead of cancelling them: the notification leaves the shade and the badge is cleared, while the bubble is preserved — matching the platform's swipe-dismiss behavior.

• Expanded bubbles, and conversations currently on screen, keep their previous behavior.
• Notifications with bubble metadata but no active bubble (FLAG_BUBBLE not set) are cancelled outright as before.
• Bubble notifications are reported as "not cancelled" so the message group summary is kept alive; cancelling the summary can cancel its suppressed bubbled children along with it.
• On API 30, background suppression has no effect, so previous behavior is preserved there.
• The bubble metadata is re-posted in its original form (intent-based or shortcut-based).

Tested on a Samsung Galaxy S23 (Android 15): collapsed bubbles (1:1 and group) survive cross-device read with the shade entry and badge cleared; expanded bubbles, fullscreen conversations, and non-bubbled notifications behave as before.