Use new interface to call FindChangedPathsRequest GRPC

What does this MR do and why?

Contributes to #356094 (closed)

Problem

commits field in FindChangedPathsRequest was deprecated. See: gitaly!4597 (merged)

Solution

Use requests field to provide a list of commits. It should be fully compatible with a previous version.

How to set up and validate locally

In Rails console

repository = Project.find(3).repository

previous_paths = repository.find_changed_paths(['0e5660917f0316a2197ffc5add7a8f01d3e428be', '2a410f31b633ec5a994ecf1ff39dc8ffb9c6f828'])

Feature.enable(:find_changed_paths_new_format)

reload! 

new_paths = repository.find_changed_paths(['0e5660917f0316a2197ffc5add7a8f01d3e428be', '2a410f31b633ec5a994ecf1ff39dc8ffb9c6f828'])

previous_paths.map(&:path) == new_paths.map(&:path) # expected to be true

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.