Because epic index page includes also epics from subgroups
it's necessary to also get descendant group labels for filtering.
https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/4773#note_61236542

In some situations (listing labels for epics) we want to
list only group ancestor labels, this is already supported
in LabelsFinder we just need to enable additional parameters.

Also `set_issuables_index` method now loads project labels only if
@project is set (which is not used for epic group labels).

Closes gitaly#1046

Signed-off-by: NRémy Coutable <remy@rymai.me>

Signed-off-by: NRémy Coutable <remy@rymai.me>

Move it to Members::ApproveAccessRequestService.

Also, note that there was a double audit event log for access request
destruction.
Signed-off-by: NRémy Coutable <remy@rymai.me>

Previously, these wouldn't count issues or MRs in subgroups - meaning that if
_this_ group had no issues or MRs, we'd show the empty state, which was wrong.

(#42643)

By extracting a new `filter_items` method, we can override that in the
IssuesFinder and MergeRequestsFinder separately, so we don't need checks that
the model is the correct one, because we can just use the class we're in to know
that.

We can do the same for the VALID_PARAMS constant, by making it a class method.

See https://gitlab.com/gitlab-org/gitlab-ce/issues/43261

This reverts merge request !16968

Closes #26466.

[10.4] Fix GH namespace security issue

- Move the exception handling as close to the source as possible to
avoid leaking Psych ahstraction
- Also remove unnecessary rescue all statement from LintsController.
This should not be necessary anymore since any YAML errors should all be
caught by the #validation_message method.