Previously when a merge request was created, the `after_create` Rails
callback would fire the `FetchSourceBranch` Gitaly RPC. However, this
call is made inside a database transaction, which may have an idle in
transaction timeout.

On GitLab.com, this timeout is set to 30 seconds, so any
`FetchSourceBranch` calls taking longer than 30 seconds causes the
database connection to be terminated quietly. When Rails attempts to
make another database write (e.g. writing the metrics), the query
fails with a 500 error after the RPC completed, usually because a
subsequent query ran into an error.

Instead of failing after the idle in transaction, this commit will
cause the query to be killed if the total Web request time expires (60
seconds or so). While this isn't ideal, this is better than the
alternative because we should never hold open a database transaction
for a long Gitaly call. Gitaly team has a few optimizations for
`FetchSourceBranch` in the works, but allowing this RPC to run for up
to 60 seconds during a Web request is better than the status quo.

Relates to https://gitlab.com/gitlab-org/gitlab/-/issues/336657

Changelog: fixed

[bug-fix] Copy button in Enable Review App modal is broken

See merge request gitlab-org/gitlab!80561

- https://gitlab.com/gitlab-org/gitlab/-/merge_requests/80561

Changelog: fixed

Add a section to get started with the newly provisioned cluster

See merge request gitlab-org/gitlab!81011

Reverting deprecation MR for Self-Monitoring

See merge request gitlab-org/gitlab!81059

Update Group Policy Pending Membership Specs

See merge request gitlab-org/gitlab!81045

Test each role rather than just developer

Update Project Policy Pending Membership Specs

See merge request gitlab-org/gitlab!81047

Test each role rather than only developer

Reverting Self-Monitoring Documentation Deprecation Announcement

See merge request gitlab-org/gitlab!81058

This reverts merge request !76891

Add Limits to Definition of Done

See merge request gitlab-org/gitlab!80243

This reverts merge request !80535

Update What Warrants a Changelog Entry for Documentation Changes

See merge request gitlab-org/gitlab!81050

Clean up spec labels

See merge request gitlab-org/gitlab!80981

Add metrics to training link on vulnerability details page

See merge request gitlab-org/gitlab!80643

Utilize Nokogiri streaming capabilities for CoverageReportWorker

See merge request gitlab-org/gitlab!79866

- Parse xml per class node instead of whole file

Add diagram for membership types

See merge request gitlab-org/gitlab!80120

Document ARM architecture support in agentk

See merge request gitlab-org/gitlab!80987

Add GitOps secrets management page

See merge request gitlab-org/gitlab!80947

Rewrite search input styles for webkit

See merge request gitlab-org/gitlab!80479

This reverts commit 97b92b23dc64f40d2380bebf7fc512fc8498e81b.

Update Gitaly version

See merge request gitlab-org/gitlab!81044

Adds crossProjectPipelineAvailable to NamespaceType

See merge request gitlab-org/gitlab!80381

Don't return 500 error in Commits API when repository is missing

See merge request gitlab-org/gitlab!80410

Add initialize with readme checkbox in repo creation for registration flow

See merge request gitlab-org/gitlab!79770

Changelog: added

Revert https related changes to webpack config

See merge request gitlab-org/gitlab!81031

CTRT update for value stream analytics

See merge request gitlab-org/gitlab!80491

Link to supported schema versions

See merge request gitlab-org/gitlab!80692

This adds tracking to capture the click of the security training link
on the vulnerablity details page.

Respect webpack live reload setting

See merge request gitlab-org/gitlab!81030