[`CLAP`] Fix few broken things
# What does this PR do?

This PR fixes the forward pass that was broken in the `main` branch of `transformers` for `ClapModel`. To reproduce:

```python
from datasets import load_dataset
from transformers import ClapModel, ClapProcessor

dataset = load_dataset('ashraq/esc50')
input_text = ["Sound of a dog", "Sound of vaccum cleaner"]
audio_sample = dataset["train"]["audio"][-1]['array']

model_id = "ybelkada/clap-htsat-unfused"

processor = ClapProcessor.from_pretrained(model_id)
model = ClapModel.from_pretrained(model_id)

input_text = processor.tokenizer(input_text, return_tensors="pt", padding=True)
input_sample = processor.feature_extractor(audio_sample, return_tensors="pt")

out = model(input_ids=input_text.input_ids, attention_mask=input_text.attention_mask, input_features=input_sample.input_features, is_longer=input_sample.is_longer)
print(out.logits_per_audio.softmax(dim=-1)[0])
```

This PR fixes also few other nits that were missing during the bad rebase

This PR also fixes the doctest and the failing slow tests

cc @ArthurZucker @sgugger 
There are also 2 more lines that got erased, shared that with you on slack 😉 <|||||>_The documentation is not available anymore as the PR was closed or merged._<|||||>Local doctests and tests pass: 
```
============================================================ 119 passed, 39 skipped, 38 warnings in 75.88s (0:01:15) ============================================================
```