Introduce a de-dupe mechanism for push notifications

[evan-masseau]

Description

Similar to apns-collapse-id this would allow us to collapse duplicate push notifications on the device itself. In general, we assumed in the past that we'd manage de-duping this purely from the backend, but this would give us extra options, never a bad thing!

Check List

• Are you changing anything with the public API? NO
• Are your changes backwards compatible with previous SDK Versions? YES - tag is a nullable arg
• Have you tested this change on real device? NOPE
• Have you added unit test coverage for your changes? NOPE
• Have you verified that your changes are compatible with all Android versions the SDK currently supports? SHOULD!

Changelog / Code Overview

• Add extension to parse "notification_tag" out of the remote data message payload
• Use that as the tag for notifications (just like stock FCM)

Test Plan

• Test this with the sample / test app. Can easily do it with a dummy payload, don't need to update server code to be able to test.

Related Issues/Tickets

CHNL-9595

[github-actions]

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