fix(encryption): Fix mountpoint check to accept if several are found

There is no strong requirement to have only one mount for a given
 storage id. Also the error in this case would be misleading.

Signed-off-by: Côme Chilliet <come.chilliet@nextcloud.com>

lib/private/Files/Storage/Wrapper/Encryption.php

@@ -807,7 +807,7 @@ private function copyBetweenStorage(
 		// first copy the keys that we reuse the existing file key on the target location
 		// and don't create a new one which would break versions for example.
 		$mount = $this->mountManager->findByStorageId($sourceStorage->getId());
-		if (count($mount) === 1) {
+		if (count($mount) >= 1) {
 			$mountPoint = $mount[0]->getMountPoint();
 			$source = $mountPoint . '/' . $sourceInternalPath;
 			$target = $this->getFullPath($targetInternalPath);