fix(sync-dialogue): prevent cancellation via outside touch

[Alok-Silswal]

Purpose / Description

During a forced one-way / full sync, the progress dialog can currently be dismissed by tapping on the dimmed background (i.e. Outside the box).

Fixes

• Fixes Tapping outside of the progress box during a forced, one-way sync cancels the transfer #20073

Approach

• Added Cancel button to manually abort the full sync.
• Canellation logic now handles disabling of outside touch.

How Has This Been Tested?

Tested on my phone (Android 14, Xiaomi / HyperOS) using a debug build.

Outside touch no longer cancels syncing.

Videos attached as evidence.

Checklist

• You have a descriptive commit message with a short title (first line, max 50 chars).
• You have commented your code, particularly in hard-to-understand areas
• You have performed a self-review of your own code
• UI changes: include screenshots of all affected screens (in particular showing any new or changed strings) (N/A – no visual UI changes)
• UI Changes: You have tested your change using the [Google Accessibility Scanner] (N/A – no UI changes)(https://play.google.com/store/apps/details?id=com.google.android.apps.accessibility.auditor)

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Before this change:

Outside_Touch_BEFORE.mp4

After this change:

Outside_Touch_AFTER.mp4

[Alok-Silswal]

Continued from #20210 PR.

[david-allison]

Follow on from #20210

[criticalAY]

Thankyou!