Cleanup enableUseRefAccessWarning flag (#28699)

Cleanup enableUseRefAccessWarning flag

I don't think this flag has a path forward in the current
implementation. The detection by stack trace is too brittle to detect
the lazy initialization pattern reliably (see e.g. some internal tests
that expect the warning because they use lazy intialization, but a
slightly different pattern then the expected pattern.

I think a new version of this could be to fully ban ref access during
render with an alternative API for the exceptional cases that today
require ref access during render.