Issuable listings: Filter by label=Any with custom sorting results in API error

Problem

At any MR\Issue listing pages (Code Review Analytics, Issues, MRs) When filtering by label=Any with custom sorting (e.g. review_time or milestone_due_date), the API responds with an error:

Sample request:

https://gitlab.com/api/v4/analytics/code_review?project_id=278964&label_name[]=Any&page=1

Other labels (including the label=None option) work as expected.

Sentry report

https://sentry.gitlab.net/gitlab/gitlabcom/issues/1586422

Investigation

Any label filtering adds implicit grouping to the query, but doesn't add custom sorting attribute to grouping, so as a result Postgres blames that sorting attribute is not present in SELECT or GROUP part of query.

This error can happen not only at CRA but anywhere where custom sorting + label=Any is used. E.g. Issues listing or MRs listing

You can manually recreate the bug at https://gitlab.com/gitlab-org/gitlab/-/issues by using label=Any and sorting=Milestone Due Date

Fix Proposal

Here is how we handle it for other cases, so we'll need to adjust any_label scope to be aware of custom sorting too.