bedrock_endpoint() hardcoded the endpoint/host iso building it via the
result from the configured/resolved pipeline.

This change builds the bedrock URL from the resolved api_base instead.
This allows a user to override the Bedrock endpoint through the BEDROCK_API_BASE env variable.
This matches the behaviour of the other domains/llms.

Retry on empty addition

Allow bedrock endpoint override via BEDROCK_API_BASE environment variable

…n improper boolean/object frankenstein

…l cross loop RuntimeErrors that deadlock the system