ci: exclude metrics-server no-op cases from system-test matrix (#2025)

* Initial plan

* ci: exclude no-op metrics-server cases from system-test matrix

Co-authored-by: devantler <[email protected]>

---------

Co-authored-by: copilot-swe-agent[bot] <[email protected]>
Co-authored-by: devantler <[email protected]>

Author: Copilot

.github/workflows/ci.yaml

@@ -235,9 +235,10 @@ jobs:
           - "--metrics-server Disabled"
           - "--policy-engine Kyverno"
           - "--policy-engine Gatekeeper"
-        # Exclude combinations where CSI flag matches distribution × provider default behavior
+        # Exclude combinations where flags match distribution × provider default behavior
         # to avoid wasting GitHub Actions minutes on no-op tests
         exclude:
+          # CSI exclusions: no-op when flag matches distribution × provider default
           # Vanilla has no default CSI, so --csi Disabled is a no-op
           - distribution: Vanilla
             args: "--csi Disabled"
@@ -248,6 +249,16 @@ jobs:
           - distribution: Talos
             provider: Docker
             args: "--csi Disabled"
+          # Metrics Server exclusions: no-op when flag matches distribution default
+          # K3s has default metrics-server, so --metrics-server Enabled is a no-op
+          - distribution: K3s
+            args: "--metrics-server Enabled"
+          # Vanilla has no default metrics-server, so --metrics-server Disabled is a no-op
+          - distribution: Vanilla
+            args: "--metrics-server Disabled"
+          # Talos has no default metrics-server, so --metrics-server Disabled is a no-op
+          - distribution: Talos
+            args: "--metrics-server Disabled"
         # Add Talos x Hetzner combination
         include:
           - distribution: Talos