Fix input_dim and out_dim Not getting saved in model checkpoint

[aditya0by0]

✅ Summary of the Issue

When using LightningCLI, we pass --model.input_dim and --model.out_dim implicitly via parser.link_arguments() (e.g. linking from data.feature_vector_size and data.num_of_labels).

However, these values appear as null in the generated model_checkpoint.ckpt file, even though they are correctly assigned at runtime.

🔍 Root Cause

This is due to the fact that:

LightningCLI saves the hparams file before linked arguments are computed and applied.

As a result, any parameters set via parser.link_arguments(...) (such as input_dim, out_dim, etc.) are not yet populated when the configuration is saved — leading to them showing up as null in hparams.

✅ What This PR Does

• Explicitly adds input_dim and out_dim to self.hparams to ensure they are captured at runtime, even if linked.

[sfluegel05]

After merging the dev branch (which passes the unittests) into this branch (which also passes the unittests), the tests suddenly fail with the same error as in #99