Retry `after_import_service`

Problem to solve

It seems that in some circumstances execution of AfterImportService timeouts on gitaly for:

repository.delete_all_refs_except(RESERVED_REF_PREFIXES)

Exception is raised: GRPC::DeadlineExceeded, which breaks the import process.

This looks like retryable operation, that is is likely to succeed after second time with very little impact for the application

I would assume that we retry that 2-3 times to increase the chances of this succeeding.

NOTE We should use the same solution we used for post import in #39107 (closed) - ImportFailureService - with_retry