Generate snow provider environment variable map using management components

[cxbrowne1207]

Issue #, if available:

Context:

The newly introduced upgrade management-components commands is currently building a new cluster spec and running validations against it. We do not want to do this because the users cluster spec updates are not applied while upgrading management components. Specifically, one problem that arises is that if your cluster is currently running a deprecated version of Kubernetes in EKS Anywhere (right now Kubernetes 1.24), the CLI will fail upgrading the management components when building the new cluster spec.

Error: failed to upgrade cluster: unable to get cluster config from file: kubernetes version 1.24 is not supported by bundles 

This is because Kubernetes 1.24 is not supported now and does not exist in the new bundles .

As a solution to this, we want to remove the need to build the new full cluster.Spec in the upgrade management-components workflow. For this to be possible, we need to remove the need for the cluster.Spec when accessing management component information during the upgrade.

Description of changes:
This PR changes the snow provider to generate the environment variable map information using management components. It still uses the *cluster.Spec (presumably the current cluster spec) for any addition information, for snow the credentials secret

Testing (if applicable):

Documentation added/planned (if applicable):

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[eks-distro-bot]

Skipping CI for Draft Pull Request.
If you want CI signal for your change, please convert it to an actual PR.
You can still manually trigger a test run with /test all

[codecov]

Codecov Report

Attention: 37 lines in your changes are missing coverage. Please review.

Comparison is base (4583834) 73.48% compared to head (b70a403) 73.56%.
Report is 47 commits behind head on main.

Files	Patch %	Lines
pkg/workflows/management/create_workload.go	0.00%	5 Missing and 1 partial ⚠️
pkg/providers/tinkerbell/validate.go	73.68%	4 Missing and 1 partial ⚠️
release/api/v1alpha1/artifacts.go	0.00%	4 Missing ⚠️
pkg/workflows/management/secrets.go	80.00%	3 Missing ⚠️
pkg/clustermanager/cluster_manager.go	88.23%	2 Missing ⚠️
pkg/providers/nutanix/controlplane.go	92.00%	1 Missing and 1 partial ⚠️
pkg/providers/snow/snow.go	0.00%	2 Missing ⚠️
pkg/workflows/workload/create_gitops.go	84.61%	2 Missing ⚠️
pkg/workflows/workload/post_delete.go	84.61%	2 Missing ⚠️
cmd/eksctl-anywhere/cmd/deletecluster.go	0.00%	1 Missing ⚠️
... and 8 more

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #7568      +/-   ##
==========================================
+ Coverage   73.48%   73.56%   +0.07%     
==========================================
  Files         579      580       +1     
  Lines       36357    36504     +147     
==========================================
+ Hits        26718    26854     +136     
- Misses       7875     7887      +12     
+ Partials     1764     1763       -1     

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[g-gaston]

/lgtm

[cxbrowne1207]

/approve

[eks-distro-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: cxbrowne1207

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