Fix Gitaly duration timings of RefService RPCs
For many Gitaly RPCs, previously the gitaly_duration_s
log timings
only accounted for the initial request/response time. We now measure
the total time it takes to consume the response for the following RPCs:
- FindAllBranches
- FindAllRemoteBranches
- FindAllBranchNames
- FindAllTagNames
- ListNewCommits
- ListNewBlobs
- FindLocalBranches
- FindAllTags
- ListBranchNamesContainingCommit
- GetTagMessages
This came up in #222247 (closed).
Part of #30334 (closed)
Edited by Sean Carroll