Sync snippet after git action

What does this MR do?

In #39176 (closed) and #39199 (closed) we updated the snippet services to, besides updating the database, update the snippet repository.

Nevertheless, now that users will be able to update the snippet through git, we need to keep up to date the snippet db info with these changes. Mostly, because for the MPV, snippet repositories will only allow 1 file to be present.

In this MR we update the PostReceive service to update the snippet db record as well.

Refs #39265 (closed)

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• [ ] Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content