restore handling of override_settings

[DenOfEquity]

I've prevented overrides for checkpoint and vae, guessing that was why this was originally removed (testing suggests that checkpoint/vae overrides are currently not set from infotext anyway). Also noted that Quicksettings overrides can still apply.

https://github.com/lllyasviel/stable-diffusion-webui-forge/issues/1455

[lllyasviel]

This is adding another layer of complexity to maintain and we are going to set it on hold until every other things are almost fixed

[DenOfEquity]

closing as superseded by #2027