fix(synchronize-file): sync with server npe

[alperozturk96]

Issue

Exception java.lang.NullPointerException:
  at com.owncloud.android.operations.SynchronizeFileOperation.syncWithServer (SynchronizeFileOperation.kt:123)
  at com.owncloud.android.operations.SynchronizeFileOperation.run (SynchronizeFileOperation.kt:109)
  at com.owncloud.android.lib.common.operations.RemoteOperation.execute (RemoteOperation.java:132)
  at com.owncloud.android.lib.common.operations.RemoteOperation.execute (RemoteOperation.java:141)
  at com.owncloud.android.operations.common.SyncOperation.execute (SyncOperation.java:51)
  at com.owncloud.android.ui.helpers.FileOperationsHelper.lambda$openFile$5 (FileOperationsHelper.java:316)
  at com.owncloud.android.ui.helpers.FileOperationsHelper.$r8$lambda$jabfbfrZtwxQHoPvL8OpbirU-7s (FileOperationsHelper.java)
  at com.owncloud.android.ui.helpers.FileOperationsHelper$$ExternalSyntheticLambda9.run (D8$$SyntheticClass)
  at java.lang.Thread.run (Thread.java:1572)

Changes

Fixes NPE
Simplifies execution flow with FetchServerFileResult

[github-actions]

APK file: https://github.com/nextcloud/android/actions/runs/29091325009/artifacts/8227019331
To test this change/fix you can simply download above APK file and install and test it in parallel to your existing Nextcloud app.
(please click on link to get QR code displayed)

[github-actions]

Codacy

SpotBugs

Category	Base	New
Bad practice	32	32
Correctness	66	66
Dodgy code	213	213
Experimental	1	1
Malicious code vulnerability	2	2
Multithreaded correctness	29	29
Performance	41	41
Security	19	19
Total	403	403

[github-actions]

blue-Light-Screenshot test failed, but no output was generated. Maybe a preliminary stage failed.

[github-actions]

master-IT test failed: https://www.kaminsky.me/nc-dev/android-integrationTests/17314-IT-master-14-43