Add bias to gptj

[jiminha]

What does this PR do?

Transformer4.45 has the Dynamic cache updates(huggingface/transformers#31421) removing
self.bias causing the failure. Until we investigate further and update the code based on the new transformer, we are putting bias back to GaudiGPTJAttention.init()

Fixes # (issue)

GAUDI2_CI=1 RUN_SLOW=1 python3.10 -m pytest tests/test_text_generation_example.py -k token0-EleutherAI/gpt-j-6b-1

File "/usr/local/lib/python3.10/dist-packages/optimum/habana/transformers/models/gptj/modeling_gptj.py", line 124, in _attn
causal_mask = self.bias[:, :, key_length - query_length : key_length, :key_length]
AttributeError: 'GaudiGPTJAttention' object has no attribute 'bias'

[jiminha]

@atakaha Could you check on this PR? Transformer4.45 has the Dynamic cache updates (huggingface/transformers#31421) which removed self.bias, and that caused an error on our side. I tried to update the model file based on their new logic but found that update_sincos_cache() also using self.bias as well. For now I put the self.bias back to our model file so the test goes through. Could you please review the transformer PR31421 and then see if you can update the gptj model file accordingly?

[atakaha]

looks good to me.
I'll study how to apply the PR to GPTJ.