VLCMetadataService: Use 2 threads on desktop platforms

4 jobs for !315 with use_multiple_parser_threads in 3 minutes and 29 seconds (queued for 4 seconds)
latest merge request
Name Stage Failure
failed
win32 Test

Full log written to /builds/chouquette/medialibrary/build/meson-logs/testlog.txt
Uploading artifacts for failed job
Uploading artifacts...
/builds/chouquette/medialibrary/medialib_tests//**/test.db: found 2 matching files and directories

/builds/chouquette/medialibrary/build/meson-logs/testlog.txt: found 1 matching files and directories

Uploading artifacts as "archive" to coordinator... ok
id=736140 responseStatus=201 Created token=wFZKjYh9
Cleaning up file based variables
ERROR: Job failed: exit code 1