Fix stable consistency

[arrjon]

This pull request makes several small adjustments to the StableConsistencyModel class:

• Removed the storage of embedding_kwargs as an instance variable, since it is no longer needed after constructing self.time_emb.
• Updated the get_config method to serialize the time_emb object directly instead of the original embedding arguments, ensuring model configuration accurately reflects the state of the embedding.
• In compute_metrics, removed redundant division by self.sigma when passing input x to _apply_subnet in f_teacher, ensuring correct normalization.
• In the same function, fixed a bug by passing the correctly normalized input (xt / self.sigma) to _apply_subnet instead of x / self.sigma.

[codecov]

Codecov Report

❌ Patch coverage is 50.00000% with 2 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...able_consistency_model/stable_consistency_model.py	50.00%	2 Missing ⚠️

Files with missing lines	Coverage Δ
...able_consistency_model/stable_consistency_model.py	21.13% <50.00%> (+0.81%)	⬆️