Use APIServerExternalAddress from cluster status in Kubeconfigs shared/downladed via dashboard

[ahmedwaleedmalik]

What this PR does / why we need it: Follow up of https://github.com/kubermatic/kubermatic/pull/13562; this adds a special case where if the APIServerExternalAddress exists in the Cluster status then it's going to be used for all the kubeconfigs that can be downloaded via the dashboard.

Which issue(s) this PR fixes:

Fixes #

What type of PR is this?

/kind feature

Special notes for your reviewer:

Does this PR introduce a user-facing change? Then add your Release Note here:

NONE

Documentation:

NONE

[kubermatic-bot]

LGTM label has been added.

Git tree hash: 5211d8780b4e539aeb45faad5e72cd4f2cfa432f

[kubermatic-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: Waseem826

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