Execute each tool call exactly once during streaming

Resolved a bug in parse_tool_calls where shared dictionary references across parsed tool calls would cause the same tool to be executed multiple times during streaming. Each tool call is now constructed from an independent copy, eliminating the duplication.

‍

Details:

Fixes duplicate tool executions that occurred in streaming mode when multiple tool calls were parsed in the same pass
Caused by a mutable shared dict reference being reused across tool call objects in parse_tool_calls
No configuration changes required; the fix applies automatically to all streaming tool call workflows