Invoke API requestMetadata support

[JGoutin]

Invoke model API now support requestMetadata in botocore>=1.43.12 (to specify in pyproject.yml):

https://docs.aws.amazon.com/boto3/latest/reference/services/bedrock-runtime/client/invoke_model.html

The following header is also supported and should be supported globally: X-Amzn-Bedrock-Request-Metadata

{
  "requestMetadata":{
    "shape":"RequestMetadataJson",
    "documentation":"<p>Key-value pairs that you can use to filter invocation logs.</p>",
    "location":"header",
    "locationName":"X-Amzn-Bedrock-Request-Metadata"
  }
}