Support more than 1 shape/attention_params for DotProductAttention decision cache

[parthmannan]

Currently, DotProductAttention caches decisions like get_attention_backend for 1 set of attention_params and this helps reduce CPU overhead in the DotProductAttention call. However, when using model architectures with more than 1 shape for Attention (for example, Self and Cross Attention), this caching fails as it resets each time the params change.
This is a feature request to support more than 1 attention_params in the cache. Ideally this number can be configurable as some models tend to have more than 2 shapes as well but maybe 4 can be a safe number to start (if not configurable).