Remove the need to fetch helm charts when editing an RKE1 cluster

[richard-cox]

Internal Reference: ~SURE-7218~ A workaround has been found (using new OCI helm repo support to restrict number of third-party charts fetched)

Is your feature request related to a problem? Please describe.

• The create/edit component for prov clusters fetches (all) charts
• It does this to allow the user to choose to deploy RKE2 via cluster template and also if RKE2 is selected (to handle addon configuration)
• However when a user goes to Edit an RKE1 cluster we're still fetching the charts. For systems with a large number of charts this results in a step which can take a while to complete... which isn't needed

Describe the solution you'd like

• We should optimise the component to not fetch those charts if the user is editing an existing RKE1 cluster
• This comes with the caveat that the user will hit the same long download of charts when
  • Creating a cluster
  • The Apps pages in the local / upstream cluster
  • Managing extensions
  • Possibly others as well

Additional context

• We should be very careful not to break existing cluster based functionality that depends on charts

[gaktive]

Automation may be tricky since this requires an RKE1 cluster to be created, though E2E could help out here and maybe connected to Jenkins.

[nwmac]

@richard-cox is this needed for 2.9.0?

[IsaSih]

Tests pass on v2.10-66ce2f133c38379570f59276799bebc222d9ef2d-head

Scenarios tested:

• editing an existing rke1 cluster
• Creating a new rke1, rke2 cluster
• Editing an existing k3s cluster
• The Apps page in the local cluster
• Managing extensions