Refactor model config

[JosephMarinier]

• Yield multiple validation errors at once from _check_companion_services(), not just the first one.
  For example, you could see

  2 validation errors for RunConfig
  model.pipeline.stt_params
    "api_key" required in EVA_MODEL__STT_PARAMS for deepgram STT
  model.pipeline.tts_params
    "model" required in EVA_MODEL__TTS_PARAMS for cartesia TTS
  

• Refactor model config
  • Get rid of _strip_other_mode_fields() by merging the 3 model classes into a single ModelConfig that always accepts extra EVA_MODEL__*_PARAMS environment variables, even if not used (so no need to strip anything).
  • Skip validating EVA_MODEL__* environment variables when EVA_MAX_RERUN_ATTEMPTS=0. That way, if you specify EVA_MAX_RERUN_ATTEMPTS=0, you no longer need to remove these EVA_MODEL__* environment variables from your .env file. Somewhat-breaking change: we used to skip validating EVA_MODEL__* environment variables when EVA_FORCE_RERUN_METRICS=True, but that could be set while there are still failed conversations to rerun, so now you have to specify EVA_MAX_RERUN_ATTEMPTS=0.
  • This removed 82 lines of code in src/eva/models/config.py.

[gabegma]

Awesome! I tried it on an existing run where I had some errors, and I had an annoying error, unrelated to your changes. II will push it here - you can revert it if you want. :)

[raghavm243512]

Looks great.

Definitely something I should have just done when I added the ALM instead of making this mess