chore(auth): Remove amplitude from auth-server

[nshirley]

Because

• Amplitude is no longer used, and logs near every request
• And we want to reduce redundant logging

This pull request

• Removes amplitude from auth-server

Issue that this pull request solves

Checklist

Put an x in the boxes that apply

• My commit is GPG signed.
• If applicable, I have modified or added tests which pass locally.
• I have added necessary documentation (if appropriate).
• I have verified that my changes render correctly in RTL (if appropriate).
• I have manually reviewed all AI generated code.

How to review (Optional)

• Key files/areas to focus on:
• Suggested review order:
• Risky or complex parts:

Screenshots (Optional)

Please attach the screenshots of the changes made in case of change in user interface.

Other information (Optional)

Original PR is here. This is just the auth-server part to keep the PR's more manageable and lower risk