https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/26248 added
support for deduplicating FindCommit requests using Gitaly ref name
caching. However, not all endpoints were covered, and in one case the
Gitaly wrapper wasn't actually surrounding the serialization step. We
can safely cache ref names between FindCommit calls for #index and #show
endpoints for merge requests and pipelines. This can significantly
reduce the number of FindCommit requests.

We're moving from using terminology related to terminals when
we refer to Websockets connections in Workhorse.
It's more appropiate a concept like channel.

Resolve "Failing group transfer disables expandable sections"

Closes #45511

See merge request gitlab-org/gitlab-ce!26837

This fixes the bug, when approver filter is provided,
but dashboard asks to enter any filter

- added suggestions to mock data
- fixed props to be not required

Adds support for start and end parameters in the #additional_metrics
endpoint of the EnvironmentsController. start and end are meant to be
unix timestamps, per the Prometheus API (as the consumer of this
endpoint will eventually be transitioned to a prometheus endpoint).
This functionality is behind the :metrics_time_window feature flag
for development.

Cache FindCommit results in pipelines view

See merge request gitlab-org/gitlab-ce!26776

For each pipeline, the controller will call `Pipeline#latest?` to
determine if the pipeline's ref is the latest for that branch.
Since it's likely that the same branches are being used in each
pipeline, we can reduce Gitaly overhead by caching the results
of the FindCommit call.