Migrate from old progress bar API to the Android 16 ProgressStyle not…

[alabiaga]

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

• Pixel 10, Android 16
• Pixel 9, Android 16
• Virtual device W, Android Y.Y.Z

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• [] 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 - N/A

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Description

Migrate Signal's use of the progress bar API to the ProgressStyle notification template.

Note that I did not apply the Live Update treatment for notifications using the progress bar API that are ongoing.
That change will be separate once I align with the Signal team on whether those should be Live Updates.

Note that Signal's usage of the NotificationCompat lib will also gracefully fallback on the previous implementation as seen here in the NotificationCompat apply method.

https://cs.android.com/androidx/platform/frameworks/support/+/androidx-main:core/core/src/main/java/androidx/core/app/NotificationCompat.java;l=5324?q=notificationcompat&ss=androidx%2Fplatform%2Fframeworks%2Fsupport

[alabiaga]

cc @alex-signal