Update dashboards from upstream

[samuelallan72]

This includes fixes:

• 916716: Fix datasource for openstack dashboard | https://review.opendev.org/c/openstack/sunbeam-charms/+/916716
• 916851: Replace hardcoded intervals with $__rate_interval | https://review.opendev.org/c/openstack/sunbeam-charms/+/916851
• 916855: Fix grid positions for hypervisor dashboard | https://review.opendev.org/c/openstack/sunbeam-charms/+/916855

To test this PR, run:

make check-dashboard-updates

And verify all OK.

[samuelallan72]

Thanks for reviews, merged. :)