Improve load of complex json objects. Use it to pick tool, run code

Gemini doesn't work well when trying to output json objects. Using it
to output raw json strings with complex, multi-line structures
requires more intense clean-up of raw json string for parsing

tests/test_conversation_utils.py

@@ -104,6 +104,18 @@ class TestTruncateMessage:
         assert truncated_chat_history[0] != copy_big_chat_message
 
 
+def test_load_complex_raw_json_string():
+    # Arrange
+    raw_json = r"""{"key": "value with unescaped " and unescaped \' and escaped \" and escaped \\'"}"""
+    expeced_json = {"key": "value with unescaped \" and unescaped \\' and escaped \" and escaped \\'"}
+
+    # Act
+    parsed_json = utils.load_complex_json(raw_json)
+
+    # Assert
+    assert parsed_json == expeced_json
+
+
 def generate_content(count):
     return " ".join([f"{index}" for index, _ in enumerate(range(count))])