Fix wrong type checking in convert_diffusers_to_original_stable_diffusion.py

[apolinario]

This fixes the text_enc_dict: dict[str, torch.Tensor] that is erroring out:

Traceback (most recent call last):
  File "convert_diffusers_to_original_stable_diffusion.py", line 212, in <module>
      def convert_text_enc_state_dict_v20(text_enc_dict: dict[str, torch.Tensor]):
TypeError: 'type' object is not subscriptable

Another solution would be to add a from typing import Dict, but since we don't type check anywhere I think removing the dict[str, torch.Tensor] as done in this PR makes more sense.

cc @lawfordp2017

[apolinario]

Also @lawfordp2017, this line seems weird to me, I'm removing that too https://github.com/huggingface/diffusers/blob/main/scripts/convert_diffusers_to_original_stable_diffusion.py#L263.

[HuggingFaceDocBuilderDev]

The documentation is not available anymore as the PR was closed or merged.

[patrickvonplaten]

Thanks!