increase FilesyncImport priority for source flavors
PLAT-534
Check isSourceAsset only for flavor assets.
We need to do the check if the file sync f of type flavor asset and of
sub type data before doing "getIsOriginal" since this is relevant only
to media assets file syncs.
Merge pull request #635 from kaltura/IX-9.7.0-PLAT-534

increase FilesyncImport priority for source flavors