Address review: robust regex and comment accuracy

- Fix extract_packed_value regex to handle commas in entity names
  by matching C++ string literals instead of [^,]+
- Only describe dc/uom/icon in comments when their index is actually
  non-zero, so comment matches what was packed

tests/component_tests/helpers.py

@@ -9,7 +9,11 @@ INTERNAL_BIT = 1 << 24
 
 def extract_packed_value(main_cpp: str, var_name: str) -> int:
     """Extract the third (packed) argument from a configure_entity_ call."""
-    pattern = rf"{re.escape(var_name)}->configure_entity_\([^,]+,\s*\w+,\s*(\d+)\)"
+    pattern = (
+        rf"{re.escape(var_name)}->configure_entity_\("
+        r'"(?:\\.|[^"\\])*"'
+        r",\s*\w+,\s*(\d+)\)"
+    )
     match = re.search(pattern, main_cpp)
     assert match, f"configure_entity_ call not found for {var_name}"
     return int(match.group(1))