[CI] Add service accounts to runner pods

This patch attaches the previously setup service accounts to the runner pods so
that they actually have permission to read/write the buckets.

Author: boomanaiden154

premerge/linux_runners_values.yaml

@@ -11,6 +11,7 @@ template:
     annotations:
       cluster-autoscaler.kubernetes.io/safe-to-evict: "false"
   spec:
+    serviceAccount: linux-runners-ksa
     tolerations:
     - key: "premerge-platform"
       operator: "Equal"

premerge/windows_2022_runner_values.yaml

@@ -11,6 +11,7 @@ template:
     annotations:
       cluster-autoscaler.kubernetes.io/safe-to-evict: "false"
   spec:
+    serviceAccount: windows-runners-ksa
     tolerations:
     - key: "node.kubernetes.io/os"
       operator: "Equal"