feat: add route to validate email if australian institute

[amandazhuyilan]

Description

AAI-814: Add route to check if email is an Australian institute, using the list maintained by Galaxy Australia.

Changes

• Added GET /utils/register/check-australian-research-institution?email=<email> endpoint returning { "is_australian_research_institution": true/false }
• Added services/institutions.py — delegates validation to Galaxy Australia's existing institution/validate API rather than maintaining a local domain list; returns false gracefully on any upstream error or timeout
• Added tests in test_utils.py using respx to mock the Galaxy AU API: valid, invalid, upstream 500, upstream timeout, and missing query param

Checklist

• I have commented my code, particularly in hard-to-understand areas
• I have added unit / integration tests that prove my fix is effective or that my feature works
• I have run all tests locally and they pass
• I have updated the documentation (if applicable)
• For any new secrets, I have updated the shared spreadsheet and the GitHub Secrets.

How to Test Manually (if necessary)

uv run pytest

[minh-biocommons]

Looks good to me, just 1 small change requested

[marius-mather]

good to go

Seems like we are sticking with the register in the route to bypass with