Add User-Agent header to OAuth login requests

Author: jake-low

images/dashboard/src/routes/login_routes.py

@@ -111,6 +111,7 @@ async def redirect_sandbox(request: Request, code: str, state: str = None, db: S
     try:
         # Get user data
         oauth = OAuth2Session(client_id=client_id, redirect_uri=redirect_uri, scope=osm_instance_scopes)
+        oauth.headers["User-Agent"] = "OSM US Sandbox Dashboard (https://github.com/osm-sandbox/osm-sandbox-dashboard)"
         oauth.register_compliance_hook("access_token_response", lambda r: (logging.info(f"Token endpoint response: {r.status_code} {r.text}"), r)[1])
         oauth.fetch_token(
             f"{osm_instance_url}/oauth2/token", code=code, client_secret=client_secret