### What happened?

When making a request to a Bedrock Claude model **without** the `tools=` parameter, LiteLLM throws an `UnsupportedParamsError` instead of processing the request normally.

**Error message:** ``` litellm.UnsupportedParamsError: Bedrock doesn't support tool calling without `tools=` param specified. Pass `tools=` param OR set `litellm.modify_params = True` // `litellm_settings::modify_params: True` to add dummy tool to the request. Received Model Group=us.anthropic.claude-opus-4-5-20251101-v1:0 Available Model Group Fallbacks=None ```

This error occurs on legitimate requests that simply don't need tools - for example, conversation summarization/compaction calls made by AI assistants when approaching context limits.

### Expected behavior

LiteLLM should handle requests without `tools=` parameter normally, just like direct Bedrock/Claude API calls work. The Bedrock Converse API supports requests without tools.

### The suggested workaround is problematic

The error message suggests using `modify_params = True`, but this workaround has its own issues - see #17990 where `modify_params = True` breaks prefix handling in Bedrock. Users shouldn't have to choose between t…