csharp: Fixes repeated method names.

csharp: Fixes repeated method names.

Summary:
After D8397, interfaces have the I prefix again, so the "Do" prefix on
methods with repeated names may not be needed for them in most cases.

This commit also consolidates the method_managed_name calls with the
overload receiving attributes::function_def instead of plain name.

Fixes T7791

Depends on D8645

Reviewers: vitor.sousa, felipealmeida, segfaultxavi

Reviewed By: segfaultxavi

Subscribers: cedric, #reviewers, #committers

Tags: #efl

Maniphest Tasks: T7791

Differential Revision: https://phab.enlightenment.org/D8650