Swap out hooks test charms with juju controlled charms

Charms the juju team don't control shouldn't be used as test charms, as
they're liable to change in unpredictable ways, which can break our tests

juju-qa-test and juju-qa-dummy-subordinate in
run_reboot_monitor_state_cleanup

tests/suites/hooks/reboot.sh

@@ -82,19 +82,17 @@ run_reboot_monitor_state_cleanup() {
 
 	ensure "${model_name}" "${file}"
 
-	# mysql charm does not have stable channel, so we use edge channel
-	juju deploy mysql --channel=edge --force --series jammy
-	# Deploy mysql/rsyslog-forwarder-ha. The latter is a subordinate
-	juju deploy rsyslog-forwarder-ha
-	juju integrate rsyslog-forwarder-ha mysql
-	wait_for "mysql" "$(idle_condition "mysql")"
-	wait_for "rsyslog-forwarder-ha" "$(idle_subordinate_condition "rsyslog-forwarder-ha" "mysql")"
+	juju deploy juju-qa-test --base ubuntu@22.04
+	juju deploy juju-qa-dummy-subordinate
+	juju integrate juju-qa-test dummy-subordinate
+	wait_for "juju-qa-test" "$(idle_condition "juju-qa-test" 1)"
+	wait_for "dummy-subordinate" "$(idle_subordinate_condition "dummy-subordinate" "juju-qa-test")"
 
 	# Check that the reboot flag files have been created for both the charm and
 	# the subordinate. Note: juju ssh adds whitespace which we need to trim
 	# with a bit of awk magic to ensure that our comparisons work correctly
 	echo "[+] Verifying that reboot monitor state files are in place"
-	num_files=$(juju ssh mysql/0 'ls -1 /var/run/juju/reboot-monitor/ | wc -l' 2>/dev/null | tr -d "[:space:]")
+	num_files=$(juju ssh juju-qa-test/0 'ls -1 /var/run/juju/reboot-monitor/ | wc -l' 2>/dev/null | tr -d "[:space:]")
 	echo "   | number of monitor state files: ${num_files}"
 	if [ "$num_files" != "2" ]; then
 		# shellcheck disable=SC2046
@@ -104,11 +102,11 @@ run_reboot_monitor_state_cleanup() {
 
 	# Remove subordinate and ensure that the state file for its monitor got purged
 	echo "[+] Verifying that reboot monitor state files are removed once a subordinate gets removed"
-	juju remove-relation rsyslog-forwarder-ha mysql
-	wait_for "mysql" "$(idle_condition "mysql")"
+	juju remove-relation juju-qa-test dummy-subordinate
+	wait_for "juju-qa-test" "$(idle_condition "juju-qa-test" 1)"
 
-	wait_for_subordinate_count "mysql"
-	num_files=$(juju ssh mysql/0 'ls -1 /var/run/juju/reboot-monitor/ | wc -l' 2>/dev/null | tr -d "[:space:]")
+	wait_for_subordinate_count "juju-qa-test"
+	num_files=$(juju ssh juju-qa-test/0 'ls -1 /var/run/juju/reboot-monitor/ | wc -l' 2>/dev/null | tr -d "[:space:]")
 	echo "   | number of monitor state files: ${num_files}"
 	if [ "$num_files" != "1" ]; then
 		# shellcheck disable=SC2046