Display correct error message when passing Cluster based resource without ClusterClass as part of cluster create

[anujc25]

What this PR does / why we need it

• Display correct error message when passing Cluster based resource without ClusterClass as part of cluster create

Currently, when user passes Cluster resource as part of tanzu cluster create --file <input.yaml> and the cluster resource doesn't include ClusterClass as part of .spec.topology.cluster thrown proper error message.

Which issue(s) this PR fixes

Fixes #3054

Describe testing done for PR

• Added unit tests
• Manually verified by passing --dru-run output to tanzu cluster create --file <manifest.yaml> and verified the error message

Release note

Display correct error message when passing Cluster resource without ClusterClass as part of cluster create

Additional information

Special notes for your reviewer

[github-actions]

Cluster Generation A/B Results:
https://storage.googleapis.com/tkg-clustergen/3053/20220802010526/clustergen.diff.txt
Author/reviewers:
Please review to verify that the effects on the generated cluster configurations are exactly what the PR intended, and give a thumbs-up if so.

[codecov]

Codecov Report

Merging #3053 (36da3fe) into main (1c29154) will decrease coverage by 0.08%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main    #3053      +/-   ##
==========================================
- Coverage   44.23%   44.14%   -0.09%     
==========================================
  Files         416      416              
  Lines       42143    42225      +82     
==========================================
  Hits        18641    18641              
- Misses      21780    21868      +88     
+ Partials     1722     1716       -6     

Impacted Files	Coverage Δ
pkg/v1/tkg/tkgctl/helpers.go	58.68% <100.00%> (+0.28%)	⬆️
addons/pkg/crdwait/crd_wait.go	0.00% <0.00%> (-72.14%)	⬇️
pkg/v1/tkg/tkgctl/pacific_cluster.go	0.00% <0.00%> (-50.00%)	⬇️
pkg/v1/tkg/tkgctl/featuregate_helper.go	16.66% <0.00%> (-2.69%)	⬇️
pkg/v1/tkg/tkgpackageclient/package_update.go	83.57% <0.00%> (-1.43%)	⬇️
...ons/controllers/packageinstallstatus_controller.go	77.99% <0.00%> (-1.16%)	⬇️
addons/webhooks/clusterbootstrap_webhook.go	24.03% <0.00%> (-0.29%)	⬇️
cmd/cli/plugin/cluster/get.go	6.16% <0.00%> (-0.03%)	⬇️
pkg/v1/tkg/client/init.go	0.00% <0.00%> (ø)
... and 5 more

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[github-actions]

Cluster Generation A/B Results:
https://storage.googleapis.com/tkg-clustergen/3053/20220802183129/clustergen.diff.txt
Author/reviewers:
Please review to verify that the effects on the generated cluster configurations are exactly what the PR intended, and give a thumbs-up if so.

[tenczar]

LGTM

[prkalle]

LGTM

[github-actions]

Cluster Generation A/B Results:
https://storage.googleapis.com/tkg-clustergen/3053/20220803170521/clustergen.diff.txt
Author/reviewers:
Please review to verify that the effects on the generated cluster configurations are exactly what the PR intended, and give a thumbs-up if so.

[github-actions]

Cluster Generation A/B Results:
https://storage.googleapis.com/tkg-clustergen/3053/20220803170611/clustergen.diff.txt
Author/reviewers:
Please review to verify that the effects on the generated cluster configurations are exactly what the PR intended, and give a thumbs-up if so.

[chandrareddyp]

LGTM

[github-actions]

Cluster Generation A/B Results:
https://storage.googleapis.com/tkg-clustergen/3053/20220803182459/clustergen.diff.txt
Author/reviewers:
Please review to verify that the effects on the generated cluster configurations are exactly what the PR intended, and give a thumbs-up if so.

[marckhouzam]

LGTM