Projects fail to export to folder fully, if the folder gets looked at

[AveryAndrews]

Describe the issue

A project of 1.3G size takes a rather long time to export to a folder, and checking that folder seems to abort the export forever.

Reproduction steps

Steps to reproduce the behavior:

1. Make a project of size 1.3G or better
2. Export it to folder
3. Wait 2 minutes and check the export-to folder with a file manager

Expected behavior

The project should either all be there, or be there a bit later after more time has passed

Observed behavior

Project is partially exported and never fully exported, even after hours.

Screenshots and GIFs

[If applicable, add screenshots and GIFs to help explain your problem.]

QGIS (please complete the following information)

• OS: Windows 10
• QGIS Version: 3.28.4
• QFieldSync Version: 4.10.1

QField (please complete the following information)

• Device: Pixel 8 (plain, not pro)
• OS: Android 14
• QField version: 3.3.11 (f59b22 v3.3.11)]

Additional information

• Problem started happening recently, didn't happen in an older version of QField: [No], Did
  not arise with Pixel 6 PRO running earlier version of Android, but I didn't use the export function much)
• Problem can be reliably reproduced, doesn't happen randomly: [Yes]
• Problem happens with all files and projects, not only some files or projects: [Yes] all that are reasonably big.

Suggested fix:

1. add a wait wheel for export, just like the one with import, but saying 'export'.
2. export by default to the last folder exported to by that project, and only copy new/changed files