[BE] Migrate protobufs to using the new `editions` feature

Issue

Following the migration to buf.build tooling in 2024 and after the enforcement of some the protobuf API best practices therefore, we realized that some of the generated code feature excessively long entity names. One particular concern was to have all enums prefixed with the enum name twice (see PMM-12723).

Solution

As we researched the possibility of shortening the enum names by using one of the 3rd-party tools, namely alta/protopatch, we discovered a better, more natural, solution for this issue, which was contributed to by the maintainers of the protobuf library. Given the reasons explained in , we decided to wait until early 2025, when the protobuf edition 2024 is expected to be officially supported by our current proto tools. One it is available, we will migrate to edition 2024, which implements an option for shorter enum names.

For end users, this feature will only be available once:
1. protoc declares support for edition 2024 (expected early 2025).
2. protoc-gen-go declares support for edition 2024.

NOTE: while this task will bring along great maintenance benefits, it should not result in any changes for API users.