test(e2e): Don't run E2E tests on fork PRs (#5986)

Author: lforst

.github/workflows/build.yml

@@ -622,6 +622,8 @@ jobs:
 
   job_e2e_tests:
     name: E2E Tests
+    # We only run E2E tests for non-fork PRs because the E2E tests require secrets to work and they can't be accessed from forks
+    if: github.repository == 'getsentry/sentry-javascript'
     needs: [job_get_metadata, job_build]
     runs-on: ubuntu-latest
     timeout-minutes: 10