Remove max threads override for test environment (#2941)

This aligns it to the other environments for consistency.

We might choose to add this back in to all environments, but we're
instead trying to bump the rate limit from 5 to higher, which should
improve performance.

Author: tvararu

copilot/webapp/manifest.yml

@@ -90,7 +90,6 @@ environments:
       SENTRY_ENVIRONMENT: test
       MAVIS__HOST: "test.mavistesting.com"
       MAVIS__GIVE_OR_REFUSE_CONSENT_HOST: "test.mavistesting.com"
-      GOOD_JOB_MAX_THREADS: 1
   training:
     http:
       alias: