Drop Support Equinix Metal cloud provider support

[KhizerRehan]

What this PR does / why we need it:
This PR removes Equinix Metal (equinixmetal) as a supported cloud provider from OSM.

FYI: This cloud provider has been deprecated in v2.29

Dashboard Repo

• https://github.com/kubermatic/dashboard/pull/7533/changes

Kubermatic Repo

• https://github.com/kubermatic/kubermatic/pull/15317/changes
• https://github.com/kubermatic/kubermatic/pull/14827/changes
• https://github.com/kubermatic/kubermatic/pull/15064/changes

Which issue(s) this PR fixes:

Fixes #

What type of PR is this?
/kind chore
/kind cleanup

Special notes for your reviewer:

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

Removed Equinix Metal cloud provider support from Operating System Manager.

Documentation:

NONE

[kubermatic-bot]

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