[BUG] Adding a folder with blank at the end, returns lack of permissions

[mmattel]

If you found a bug:

Adding a folder with blank at the end, returns lack of permissions

Steps to reproduce

1. have a synced mount with r/w permissions
2. try create a folder having a trailing blank at the end
3. error message with lack of permissions appears

Expected behavior

Proper handling of creatable folder names

Actual behavior

Error message

Client

iOS version: 14.6

ownCloud app version: 11.6.0

Device model: iPad/iPhone

Server configuration

Web server: nginx

Database: mariadb

PHP version: 7.4

ownCloud version: 10.7

Storage backend (external storage): local, smb, gd

Logs

Web server error log

Nothing relevant

ownCloud log (data/owncloud.log)

Nothing relevant

@michaelstingl @hosy fyi