Fix Windows test

[koppor]

Follow-up to #13295

org.jabref.logic.cleanup.RenamePdfCleanupTest

  Test cleanupRenamePdfRenamesFileEvenIfOnlyDifferenceIsCase() FAILED

  org.opentest4j.AssertionFailedError: expected: <Optional[:Toot.tmp:]> but was: <Optional[:Toot (1).tmp:]>
      at app/org.jabref.jablib/org.jabref.logic.cleanup.RenamePdfCleanupTest.cleanupRenamePdfRenamesFileEvenIfOnlyDifferenceIsCase(RenamePdfCleanupTest.java:67)

Not sure if logic is broken or test is broken.

[Siedlerchr]

Windows is case insensitive!

[koppor]

Windows is case insensitive!

Not sure why "(1)" was generated then. Did you look into the code and identified the location? 😅

[Siedlerchr]

Test is green for me on mac.