app data is too large, preventing backup, in large part due to sample projects

[gdt]

Describe the issue

The android backup system (as used by SeedVault) fails to back up QField, because the amount of data in sample projects.

Reproduction steps

Install QField on Android. Long press, app info, storage. Observe something quite large, 61.39 MB in my case with one project loaded, where the project as staged for import was 2.5 MB.

Expected behavior

There is no data used in storage, except app configuration and imported project/data. In particular, sample projects are not in storage.

Arguably, "copy" layers should probably be in cache, not storage, but that's less important.

Observed behavior

There is a large amount of "storage", which is a) not expected and b) breaks backups. (Apps that are too big, are not backed up.)

QField (please complete the following information)

• Device: Pixel
• CalyxOS, Android 15 version
• QField version: 3.4.7 dfab7b (apk from github)