Fix #8241: Ensure UI back button navigates to Drafts folder when editing a draft

[sergiolpzgmz]

Issue

Fixes #8241: Closing a draft via Thunderbird's back button navigates to the inbox instead of the drafts folder.

Summary of Changes

Modified the prepareToFinish method in MessageCompose.java to check if the current action is EDIT_DRAFT. If so, the UI back button uses super.onBackPressed() instead of openDefaultFolder(), ensuring the user is navigated back to the Drafts folder instead of the Inbox. This makes the UI back button behavior consistent with the system back button.

Testing

• Tested manually by opening an existing draft, pressing the UI back button, and verifying navigation to the Drafts folder.
• Tested other flows (e.g., creating a new message, replying to a message) to ensure they are unaffected.
• Ran ./gradlew test to confirm no regressions in existing tests.

Additional Notes

I did not add new tests for this change, as it involves navigation behavior that may require UI/integration testing. I'm happy to add tests if the team provides guidance on how to test this scenario.

[wmontwe]

Thank you!

[github-actions]

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