Add prelogin metrics

[coliemcgarry]

COMPLETES #< INSERT LINK TO ISSUE >

This pull request addresses

We would like to send pre-login metrics i.e. add a new API to the new-metrics plugin to support sending metrics before the user is authenticated.

Much of the code for this already existed and was used by calling, however this uses cases are very much calling specific, so we added a non calling specific API to send pre login metics

by making the following changes

< DESCRIBE YOUR CHANGES >

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

< ENUMERATE TESTS PERFORMED, WHETHER MANUAL OR AUTOMATED >

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[arun3528]

do we need this , rather make sure agent desktop sends this, sdk or other clients might use this in future