use built-in FindOpenGL module for GLES with cmake 3.23+

[mbaetgen-wup]

[kblaschke]

Probably needs to be done in the same way in the config package script here. I also always forget about this file, as seen in the 4.1.6 PR 😆

Guess you could also squash the changes into a single commit before merging, as it's only a few lines.