Update git submodules

* Update system/core from branch 'main'
  to f6b59d19ae5152761475bc8da9600621e827eef1
  - Merge "Create OWNERS for test_upgrade_mte" into main
  - Create OWNERS for test_upgrade_mte
    
    Change-Id: I0dd6bccf9f6a1767f11fd3e687d819eceaab7b5e
    
1 file changed