[BUGFIX] Use return values of array_map in local driver

The LocalDriver will now use the return values of array_map calls in
createFolder() and determineBaseUrl() so that the values are really
sanitized / url encoded.

Resolves: #57415
Releases: 6.2
Change-Id: I8aa1a79c6e4a7fe6c2d82ec66c12338e75a35872