Allow session attributes as inputs to the invoke method for Bedrock Agents

[jicowan]

Description

Current Bedrock agent implementation does not allow passing promptSessionAttributes and sessionAttributes as inputs to the invoke method. These inputs are useful to pass in additional runtime context to the agents, for example passing in information from a user's profile, their username or location. Here is the documentation for these attributes in Bedrock agents.
https://docs.aws.amazon.com/bedrock/latest/userguide/agents-session-state.html#session-state-attributes

[3coins]

cc @jdbaker01
cc @kcgourishetti

[3coins]

@jicowan
Thanks for raising this issue. I simplified the description for the issue, and added link to the documentation. Please feel free to edit as necessary.