[stable-2.0] fix direct opening with special file names + test cases

[backportbot-nextcloud]

backport of #384

[nextcloud-android-bot]

Lint

Type	stable-2.0	PR
Warnings	0	0
Errors	0	0

SpotBugs (new)

Warning Type	Number
Bad practice Warnings	14
Correctness Warnings	39
Internationalization Warnings	6
Malicious code vulnerability Warnings	7
Multithreaded correctness Warnings	3
Performance Warnings	17
Security Warnings	1
Dodgy code Warnings	58
Total	145

SpotBugs (stable-2.0)

Warning Type	Number
Bad practice Warnings	14
Correctness Warnings	39
Internationalization Warnings	6
Malicious code vulnerability Warnings	7
Multithreaded correctness Warnings	3
Performance Warnings	17
Security Warnings	1
Dodgy code Warnings	58
Total	145

[codecov]

Codecov Report

Merging #385 into stable-2.0 will increase coverage by 0.11%.
The diff coverage is 100%.

@@              Coverage Diff               @@
##           stable-2.0     #385      +/-   ##
==============================================
+ Coverage       34.37%   34.49%   +0.11%     
==============================================
  Files             133      133              
  Lines            5728     5729       +1     
  Branches          751      751              
==============================================
+ Hits             1969     1976       +7     
+ Misses           3486     3481       -5     
+ Partials          273      272       -1

Impacted Files	Coverage Δ
...tediting/DirectEditingOpenFileRemoteOperation.java	80% <100%> (+13.33%)	⬆️
...wncloud/android/lib/resources/files/FileUtils.java	71.42% <0%> (-14.29%)	⬇️
...d/lib/common/operations/RemoteOperationResult.java	36.58% <0%> (+0.6%)	⬆️
...d/lib/resources/files/ReadFileRemoteOperation.java	79.31% <0%> (+10.34%)	⬆️