Skip expensive jobs on closed PRs

Labeling PRs causes jobs which react to labeling to be run, even if
the PR is closed (e.g. because it's already been merged). In
Submariner, this commonly happens with labels pertaining to backports
or release notes, resulting in a significant number of runner minutes
wasted on jobs that we don't care about.

This limits these jobs to PRs which are still open.

Signed-off-by: Stephen Kitt <skitt@redhat.com>

.github/workflows/cross.yml

@@ -10,7 +10,9 @@ permissions: {}
 jobs:
   cross:
     name: Cross-Build
-    if: github.event.pull_request.draft == false || contains(github.event.pull_request.labels.*.name, 'test-draft')
+    if: |
+      (github.event.pull_request.draft == false || contains(github.event.pull_request.labels.*.name, 'test-draft'))
+      && github.event.pull_request.state == 'open'
     runs-on: ubuntu-latest
     steps:
       - name: Check out the repository

.github/workflows/e2e-full.yml

@@ -10,7 +10,7 @@ permissions: {}
 jobs:
   e2e:
     name: E2E
-    if: contains(github.event.pull_request.labels.*.name, 'ready-to-test')
+    if: contains(github.event.pull_request.labels.*.name, 'ready-to-test') && github.event.pull_request.state == 'open'
     timeout-minutes: 30
     runs-on: ubuntu-latest
     strategy:

.github/workflows/upgrade-e2e.yml

@@ -11,7 +11,9 @@ permissions: {}
 jobs:
   upgrade-e2e:
     name: Latest Release to Latest Version
-    if: github.event.pull_request.draft == false || contains(github.event.pull_request.labels.*.name, 'test-draft')
+    if: |
+      github.event.pull_request.draft == false || contains(github.event.pull_request.labels.*.name, 'test-draft')
+      && github.event.pull_request.state == 'open'
     timeout-minutes: 30
     runs-on: ubuntu-latest
     strategy: