add an additional cleanup command to the self hosted runner hooks

- sometimes the images need to be manually cleaned out prior to
  running 'podman system reset --force' so add a call to 'podman rmi
  --all --force'

- this seems counter intuitive because the 'system reset --force'
  should be taking care of this -- it makes me wonder if this is a
  "bug" in an older version of podman and wouldn't be required if
  newer software levels were being used

.github/runners/self-hosted/actions-runner-hooks/job-completed.sh

@@ -1,6 +1,7 @@
 #!/bin/bash
 
 sudo buildah rm --all
+sudo podman rmi --all --force
 sudo podman system reset --force
 
 echo "Cleaning up registry authorization tokens..."

.github/runners/self-hosted/actions-runner-hooks/job-started.sh

@@ -1,6 +1,7 @@
 #!/bin/bash
 
 sudo buildah rm --all
+sudo podman rmi --all --force
 sudo podman system reset --force
 
 echo "Cleaning up registry authorization tokens..."