ci: completely remove e2e test from ci (#822)

including a test that depends on our datahub dev environment breaks
in a bunch of subtle ways:

- workflow_call triggered jobs can't access the secret, unless we
  explicitly pass it through from the parent workflows
- dependabot can't access the secret, unless we copy the secret to
  dependabot secrets
- pull requests from outside the org can't access the secret either
  either (a security measure to prevent exfiltrating secrets)

the benefit of this test is already quite minimal so this has convinced
me we don't need it in our CI pipeline.

.github/workflows/reusable-tests.yml

@@ -115,15 +115,6 @@ jobs:
         if: steps.fast-tests.outcome == 'success'
         run: make integration
 
-      # This step should be skipped when triggered by workflow_call, since these tests
-      # rely on an external environment and are somewhat flaky.
-      - name: Run end to end tests
-        if: steps.fast-tests.outcome == 'success' && github.event_name == 'pull_request'
-        run: make end_to_end
-        env:
-          CATALOGUE_TOKEN: ${{secrets.DEV_CATALOGUE_TOKEN}}
-          CATALOGUE_URL: ${{vars.DEV_CATALOGUE_URL}}
-
   javascript-only-tests:
     name: Javascript tests
     runs-on: ubuntu-latest