[stable-3.30] TextWebView: allow to upload multiple attachements

[backportbot]

Backport of PR #13546

[github-actions]

APK file: https://www.kaminsky.me/nc-dev/android-artifacts/13682.apk



To test this change/fix you can simply download above APK file and install and test it in parallel to your existing Nextcloud app.

[github-actions]

Lint

Type	stable-3.30	PR
Warnings	60	60
Errors	3	3

SpotBugs

Category	Base	New
Bad practice	63	63
Correctness	64	64
Dodgy code	300	300
Experimental	1	1
Internationalization	7	7
Multithreaded correctness	6	6
Performance	53	53
Security	18	18
Total	512	512

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 7 lines in your changes missing coverage. Please review.

Project coverage is 26.49%. Comparing base (ea19c02) to head (daffe17).
Report is 2 commits behind head on stable-3.30.

Files with missing lines	Patch %	Lines
...om/owncloud/android/ui/activity/EditorWebView.java	0.00%	7 Missing ⚠️

Additional details and impacted files

@@                Coverage Diff                @@
##             stable-3.30   #13682      +/-   ##
=================================================
+ Coverage          26.30%   26.49%   +0.18%     
- Complexity          3385     3398      +13     
=================================================
  Files                658      658              
  Lines              48207    48213       +6     
  Branches            6461     6463       +2     
=================================================
+ Hits               12681    12773      +92     
+ Misses             33591    33485     -106     
- Partials            1935     1955      +20     

Files with missing lines	Coverage Δ
...om/owncloud/android/ui/activity/EditorWebView.java	0.00% <0.00%> (ø)

... and 9 files with indirect coverage changes