Generated `ServiceStub` with rcp method "Metadata" gets overwriten by metadata parameter in parent class

[palani-johnson]

Summary

Any generated ServiceStub with an rcp that conflicts with a mutable parameter that is set in the parent class will get overwriten during parent class init.

Reproduction Steps

Generate a ServiceStub with an rcp named the same as a parameter that is set during the ServiceStub parent class initialization.

Expected Results

method is not overwritten during init

Actual Results

Method is overwritten by metadata. Attempting to call method results in TypeError: 'dict' object is not callable

System Information

betterproton2 0.10.0
python 3.13.7

Checklist

• I have searched the issues for duplicates.
• I have shown the entire traceback, if possible.
• I have verified this issue occurs on the latest prelease of betterproto which can be installed using pip install -U --pre betterproto, if possible.