CI: Run Tests workflow in pr-tests environment without deployment (#4457)

Xref https://github.blog/changelog/2026-03-19-github-actions-late-march-2026-updates/#github-actions-now-allows-developers-to-use-environments-without-auto-deployment

Author: weiji14

.github/workflows/ci_tests.yaml

@@ -51,6 +51,9 @@ jobs:
   test:
     name: ${{ matrix.os }} - Python ${{ matrix.python-version }}
     runs-on: ${{ matrix.os }}
+    environment:
+      name: pr-tests
+      deployment: false
     permissions:
       id-token: write  # This is required for requesting OIDC token for codecov
     strategy: