Use getFileNameText for nullable field

[alperozturk96]

• [x] Tests written, or not not needed

[github-actions[bot]]

Codacy

Lint

Type	master	PR
Warnings	71	71
Errors	3	3

SpotBugs

Category	Base	New
Bad practice	67	67
Correctness	72	72
Dodgy code	345	341
Experimental	1	1
Internationalization	7	7
Malicious code vulnerability	2	2
Multithreaded correctness	6	6
Performance	57	57
Security	19	19
Total	576	572

[github-actions[bot]]

APK file: https://www.kaminsky.me/nc-dev/android-artifacts/12927.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.

[AndyScherzinger]

/backport to stable-3.29