tests: filter float_precision deprecation warning

Author: parthea

pytest.ini

@@ -6,3 +6,6 @@ filterwarnings =
     ignore:.*custom tp_new.*in Python 3.14:DeprecationWarning
     # Remove once deprecated field `including_default_value_fields` is removed
     ignore:.*The argument `including_default_value_fields` has been removed.*:DeprecationWarning
+    # Remove once deprecated field `float_precision` is removed
+    # See https://github.com/googleapis/proto-plus-python/issues/547
+    ignore:float_precision option is deprecated for json_format:UserWarning