Investigate, and if possible remove, need to fetch all management clusters on load

[richard-cox]

SURE-7040

• In cases where there are LOTS of clusters this has a large impact on load of every page (10+ seconds)
• We need to understand why we need all mgmt clusters (guessing at least the burger menu) and try to address each
  • For the burger menu, we should be able to use the new pagination api to filter results to get the required max clusters to show

[moio]

@richard-cox problem is a good part of that slowness comes from Steve's need to fetch the whole collection from Kubernetes. Even if we could filter the results in Steve, the actual endpoint will likely be slow.

Do you see any option to avoid the fetch altogether? Or is it needed in many other places besides the hamburger menu?

[nwmac]

@richard-cox is this in scope for 2.14?

[richard-cox]

Good news! With vai on and cluster side bar using it we now no longer fetch all mgmt clusters on load. Linking https://github.com/rancher/dashboard/issues/15569