Regression: Provide a fallback text when push notification is idOnly

[djorkaeffalexandre]

Proposed changes

How to test or reproduce

1. Get the latest iOS beta (internal testers).
2. Enable fetch content from server on Push notification Privacy.
3. Send a notification and put your server down.
4. It will show the fallback message. (Someone send you a message)

Screenshots

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• Improvement (non-breaking change which improves a current function)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Hotfix (a major bugfix that has to be merged asap)
• Documentation Update (if none of the other choices apply)

Checklist

• I have read the CONTRIBUTING doc
• I have signed the CLA
• Lint and unit tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works (if applicable)
• I have added necessary documentation (if applicable)
• Any dependent changes have been merged and published in downstream modules

Changelog

Provide a fallback text when push notification is idOnly and can't be fetched.

Further comments