Add Prometheus memory sparkline to MR widget

Purpose of this MR

This is copy of !11030 (merged) that was already merged in !10319 (merged) but changes were lost, probably while resolving merge conflicts. Hence, this MR needs to go in %9.2

See #26944 (closed)

Screenshots

When statistics available

Statistics being loaded

When statistics not available

Multiple Deployments

Does this MR meet the acceptance criteria?

• [ ] Changelog entry added, if necessary
• [ ] Documentation created/updated
• [ ] API support added
• Tests
  • Added for this feature/bug
  • All builds are passing
• Conform by the merge request performance guides
• Conform by the style guides
• Branch has no merge conflicts with master (if it does - rebase it please)
• Squashed related commits together

What are the relevant issue numbers?

Closes #26944 (closed)

approved this merge request

merged

mentioned in commit 5354c293

This MR is already reviewed and merged by @jschatz1 but somehow it missed the merge to master. Pipeline failure was related with the failure on the master.

mentioned in issue #31934 (closed)

Picked into 9-2-stable, will go into 9.2.0-rc1

mentioned in commit 38a7f46b