feat(internal-plugin-metrics): add prelogin metrics interface to new-metrics

[CormacGCisco]

COMPLETES #CX-22317

This pull request addresses

We want to have the ability to send pre-login metrics from wxcc-desktop

by making the following changes

Exposing an API in the SDK

Change Type

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update
• Tooling change
• Internal code refactor

The following scenarios were tested

This PR also adds unit tests

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• This PR is related to
  • Feature
  • Defect fix
  • Tech Debt
  • Automation

I certified that

• I have read and followed contributing guidelines
• I discussed changes with code owners prior to submitting this pull request
• I have not skipped any automated checks
• All existing and new tests passed
• I have updated the documentation accordingly

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