Revert "fix: make --continue_path work again"

[erogol]

Reverts #131

[erogol]

@eginhard I needed to revert this PR since it cause CI issues on TTS

--> EVAL PERFORMANCE
   | > Epoch:0  AvgLoss: 5.16343 
Traceback (most recent call last):
  File "/home/runner/work/TTS/TTS/TTS/bin/train_encoder.py", line 322, in <module>
    main(args)
  File "/home/runner/work/TTS/TTS/TTS/bin/train_encoder.py", line 315, in main
    _, global_step = train(model, optimizer, scheduler, criterion, train_data_loader, eval_data_loader, global_step)
                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/runner/work/TTS/TTS/TTS/bin/train_encoder.py", line 250, in train
    best_loss = save_best_model(
                ^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.11.6/x64/lib/python3.11/site-packages/trainer/io.py", line 1[83](https://github.com/coqui-ai/TTS/actions/runs/7113455600/job/19365444297?pr=3373#step:10:84), in save_best_model
    use_eval_loss = current_loss["eval_loss"] is not None and best_loss["eval_loss"] is not None

[eginhard]

@erogol Ok... IMHO it's not really a conflict, but just shows that TTS needs to be updated for the latest Trainer version. But if you want to do it very cleanly we could do the following:

1. TTS PR that pins Trainer==0.0.34
2. Resubmit fix: make --continue_path work again #131 and release Trainer 0.0.35
3. Update TTS so that tests pass and pin Trainer>=0.0.35