build: distinguish unit test and pylint successful checks (#32452)

We will be able to use these composite checks to block
PR merges instead of blocking on every single individual
unit test and pylint check.

Closes: https://github.com/openedx/edx-platform/issues/32238

.github/workflows/pylint-checks.yml

@@ -71,7 +71,7 @@ jobs:
   # https://github.com/marketplace/actions/alls-green#why
   # https://github.com/orgs/community/discussions/33579
   success:
-    name: Tests successful
+    name: Pylint checks successful
     if: always()
     needs:
       - run-pylint

.github/workflows/unit-tests.yml

@@ -81,7 +81,7 @@ jobs:
   # https://github.com/marketplace/actions/alls-green#why
   # https://github.com/orgs/community/discussions/33579
   success:
-    name: Tests successful
+    name: Unit tests successful
     if: (github.repository == 'edx/edx-platform-private') || (github.repository == 'openedx/edx-platform' && (startsWith(github.base_ref, 'open-release') == false))
     needs:
       - run-tests