ges: Misc fixes and minor debug enhancement

• ges: uri-clip: Set error on invalid URI's in check_id
  The _check_id function signature was incomplete and the last GError
  argument was ignored instead of being properly used.

• ges-effect: Chain-up to parent constructed vfunc

• ges-asset: Propagate errors from GInitable

• ges-asset: Log asset ids in ges_asset_request

• ges-asset: Fix typo in warning message

• ges: effect: Report asset request errors

• nlecomposition: Pass object to debug messages in more places

• • ges: Minor typo fix