llama : remove quantization sanity check (#17788)

llama : remove quantization sanity check (#17788)

* llama : remove quantization sanity check

This commit removes the quantization sanity check for attention layers.

The motivation for this is that there are model that are hybrid models
that have recurrent layers, experts layers, and attention layers.  For
these models the current check fails as the experts layers are not
taking into account. After consideration, it was decided that this check
is not strictly necessary, and can be removed to allow for more flexible
model architectures.

* llama : remove unused pruned_attention_w and is_clip_model vars