Scope compositor isolation to reset tests

tests/quickshell/settings-commit-reset-contract.sh

@@ -51,7 +51,8 @@ rg -Fq 'property string storedValue:' "$wallpaper_service" \
     || fail 'the shipped wallpaper cannot remain represented by the default empty preference'
 
 qs_for_harness() {
-    XDG_CONFIG_HOME="$config_home" XDG_STATE_HOME="$state_home" qs -p "$harness" "$@"
+    XDG_CONFIG_HOME="$config_home" XDG_STATE_HOME="$state_home" \
+        PANAMA_SETTINGS_TEST_ISOLATE_COMPOSITOR=1 qs -p "$harness" "$@"
 }
 
 restore() {
@@ -60,7 +61,8 @@ restore() {
 }
 trap restore EXIT
 
-XDG_CONFIG_HOME="$config_home" XDG_STATE_HOME="$state_home" qs -p "$harness" --daemonize >/dev/null
+XDG_CONFIG_HOME="$config_home" XDG_STATE_HOME="$state_home" \
+    PANAMA_SETTINGS_TEST_ISOLATE_COMPOSITOR=1 qs -p "$harness" --daemonize >/dev/null
 for _ in $(seq 1 40); do
     qs_for_harness ipc show 2>/dev/null | rg -q '^target settings-system-test$' && break
     sleep 0.1