Ensure we are editing realm database on main thread in FileProviderEnumerator

Signed-off-by: Claudio Cambra <claudio.cambra@nextcloud.com>

shell_integration/MacOSX/NextcloudIntegration/FileProviderExt/FileProviderEnumerator.swift

@@ -560,7 +560,7 @@ class FileProviderEnumerator: NSObject, NSFileProviderEnumerator {
                 }
 
                 Logger.enumeration.debug("Starting async conversion of NKFiles for serverUrl: \(serverUrl, privacy: OSLogPrivacy.auto(mask: .hash)) for user: \(ncAccount.ncKitAccount, privacy: OSLogPrivacy.auto(mask: .hash))")
-                DispatchQueue.global().async {
+                DispatchQueue.main.async {
                     dbManager.convertNKFilesFromDirectoryReadToItemMetadatas(files, account: ncKitAccount) { directoryMetadata, childDirectoriesMetadata, metadatas in
 
                         // STORE DATA FOR CURRENTLY SCANNED DIRECTORY