removed obsolete elements from openedx.yaml (#24833)

openedx.yaml

 # This file describes this Open edX repo, as described in OEP-2:
 # https://open-edx-proposals.readthedocs.io/en/latest/oep-0002-bp-repo-metadata.html#specification
 
-owner: 'nasthagiri'
-supporting_teams:
-    - platform-core
-
 nick: edx
 openedx-release: {ref: release}