feat(dashboards): mimir runway datasource custom dashboards

What

Update custom dashboards for Runway to use Mimir - Runway default datasource.

Why

Follow-up to !7310 (merged).

Snapshot

• https://dashboards.gitlab.net/dashboard/snapshot/RokHp491bTOBi2yIV9cC33zoroJDM5uE?orgId=1
• https://dashboards.gitlab.net/dashboard/snapshot/wG1G7cNKHgrmRMP0fHEfvVDgjeV2a5yK?orgId=1