Blender Git Loki

Fix T81865, T81860: CustomData Correction can fail on non standard names

Caused by rBaafd71a8a160.

In the process of CustomData Correction, we need to make sure we also
have matching layer names [as was done before above commit], otherwise
this will create layers with default names, applying
(mesh_customdatacorrect_apply and friends) will fail then.

Maniphest Tasks: T81865

Differential Revision: https://developer.blender.org/D9278