ci: Directly check for needed secrets before testing against cloud

There are other situations besides running in a fork in which the
necessary secrets are not available.  For example, PRs opened by
dependabot do not seem to have access to the secrets.

We now directly check if secrets are present, rather than inferring
their presence from other environmental things.

.github/workflows/ci.yaml

@@ -18,6 +18,10 @@ jobs:
           - os: ubuntu-arm
             runsOn: buildjet-4vcpu-ubuntu-2204-arm
     runs-on: ${{ matrix.runsOn || matrix.os }}
+    env:
+      # We can't check this directly in the cloud test's `if:` condition below,
+      # so we have to check it here and report it in an env variable.
+      HAS_SECRETS: ${{ secrets.TEMPORAL_CLIENT_CERT != '' && secrets.TEMPORAL_CLIENT_KEY != '' }}
     steps:
       - name: Checkout repository
         uses: actions/checkout@v4
@@ -53,8 +57,7 @@ jobs:
           git diff --exit-code
 
       - name: Test cloud
-        # Only supported in non-fork runs, since secrets are not available in forks
-        if: ${{ matrix.cloudTestTarget && (github.event.pull_request.head.repo.full_name == '' || github.event.pull_request.head.repo.full_name == 'temporalio/cli') }}
+        if: ${{ matrix.cloudTestTarget && env.HAS_SECRETS == 'true' }}
         env:
           TEMPORAL_ADDRESS: ${{ vars.TEMPORAL_CLIENT_NAMESPACE }}.tmprl.cloud:7233
           TEMPORAL_NAMESPACE: ${{ vars.TEMPORAL_CLIENT_NAMESPACE }}