csharp: Rename register_event_proxies.
Summary:
To better adhere to C# conventions and state it is for generated code
only.
Ref T7702
Reviewers: vitor.sousa, segfaultxavi
Reviewed By: segfaultxavi
Subscribers: cedric, reviewers, committers
Tags: efl
Maniphest Tasks: T7702
Differential Revision: https://phab.enlightenment.org/D8369