feat: add kubevision support for instance and cluster spec

[imwithye]

This PR add kubevision support for akuity instance and cluster spec.

For Instance:

argocd:
  spec:
    version: "v2.12.3-ak.39"
    instanceSpec:
      multiClusterK8sDashboardEnabled: true

For Cluster:

clusterSpec:
  description: "This is cluster description"
  data:
    multiClusterK8sDashboardEnabled: true

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 64.73%. Comparing base (2ef19aa) to head (65f1a2a).
Report is 5 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #54      +/-   ##
==========================================
- Coverage   65.22%   64.73%   -0.49%     
==========================================
  Files          11       11              
  Lines        1182     1211      +29     
==========================================
+ Hits          771      784      +13     
- Misses        349      365      +16     
  Partials       62       62              

Flag	Coverage Δ
unittests	64.73% <100.00%> (-0.49%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.