[stable-3.18] AccountManagerService needs to be exported

[backportbot-nextcloud]

⚠️ This backport had conflicts and is incomplete ⚠️

backport of #9157

[github-actions]

APK file: https://www.kaminsky.me/nc-dev/android-artifacts/9159.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.

[nextcloud-android-bot]

Lint

Type	stable-3.18	PR
Warnings	110	125
Errors	1	0

SpotBugs (new)

Warning Type	Number
Bad practice Warnings	28
Correctness Warnings	48
Internationalization Warnings	9
Malicious code vulnerability Warnings	51
Multithreaded correctness Warnings	9
Performance Warnings	65
Security Warnings	40
Dodgy code Warnings	101
Total	351

SpotBugs (stable-3.18)

Warning Type	Number
Bad practice Warnings	28
Correctness Warnings	48
Internationalization Warnings	9
Malicious code vulnerability Warnings	51
Multithreaded correctness Warnings	9
Performance Warnings	65
Security Warnings	40
Dodgy code Warnings	101
Total	351

Lint increased!

[github-actions]

blue-Light-Screenshot test failed: https://www.kaminsky.me/nc-dev/android-integrationTests/9159-Screenshot-blue-Light-18-19

[codecov]

Codecov Report

Merging #9159 (a8d715b) into stable-3.18 (8d77bc3) will decrease coverage by 0.12%.
The diff coverage is n/a.

@@               Coverage Diff               @@
##           stable-3.18    #9159      +/-   ##
===============================================
- Coverage        31.16%   31.03%   -0.13%     
===============================================
  Files              500      500              
  Lines            38152    38152              
  Branches          5281     5281              
===============================================
- Hits             11889    11840      -49     
- Misses           24480    24565      +85     
+ Partials          1783     1747      -36     

Impacted Files	Coverage Δ
...va/com/owncloud/android/utils/FilesSyncHelper.java	14.60% <0.00%> (-6.75%)	⬇️
...cloud/android/datamodel/UploadsStorageManager.java	66.42% <0.00%> (-5.78%)	⬇️
...om/owncloud/android/utils/ErrorMessageAdapter.java	3.36% <0.00%> (-3.85%)	⬇️
.../owncloud/android/files/services/FileUploader.java	48.48% <0.00%> (-3.24%)	⬇️
...oud/android/operations/RefreshFolderOperation.java	76.51% <0.00%> (-2.50%)	⬇️
.../third_parties/daveKoeller/AlphanumComparator.java	80.95% <0.00%> (-2.39%)	⬇️
...ain/java/com/owncloud/android/db/UploadResult.java	39.74% <0.00%> (-1.29%)	⬇️
...wncloud/android/providers/FileContentProvider.java	23.82% <0.00%> (-0.51%)	⬇️
...loud/android/datamodel/FileDataStorageManager.java	57.17% <0.00%> (+0.23%)	⬆️
...ncloud/android/operations/UploadFileOperation.java	60.72% <0.00%> (+0.32%)	⬆️
... and 3 more