prompty: fix parsing of tool_calls when array in arguments (#3820)

# Description

Current regex for parsing of tool_calls breaks if there is an array in
the arguments (as it has a ']').
Consume up to end of block so it only matches the closing ']' and not
any intermediate ones.


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### Testing Guidelines
- [ ] Pull request includes test coverage for the included changes.

src/promptflow-core/promptflow/core/_prompty_utils.py

@@ -654,7 +654,7 @@ def try_parse_tool_call_id_and_content(role_prompt):
 def try_parse_tool_calls(role_prompt):
     # customer can add ## in front of tool_calls for markdown highlight.
     # and we still support tool_calls without ## prefix for backward compatibility.
-    pattern = r"\n*#{0,2}\s*tool_calls\s*:\s*\n+\s*(\[.*?\])"
+    pattern = r"\n*#{0,2}\s*tool_calls\s*:\s*\n+\s*(\[.*?\])\s*$"
     match = re.search(pattern, role_prompt, re.DOTALL)
     if match:
         try: