Fix parseModuleJson undefined call in custom command modules

CustomCommandModule.update() in Bar.qml called root.parseModuleJson(raw)
but the function was removed in 3b970068 (the indicator split). Any
custom command module emitting waybar-style JSON would have crashed on
first poll.

Hoist the helper into Util so both call sites — the bar's custom command
module and BarIndicator.extractData — share one definition.

shell/Commons/Util.qml

@@ -54,6 +54,20 @@ QtObject {
     return JSON.parse(JSON.stringify(value === undefined ? null : value))
   }
 
+  // Parse the last line of a custom-module / indicator process output as
+  // waybar-style JSON ({text, class, tooltip, ...}). Falls back to {text: raw}
+  // when the output isn't JSON, and {} for empty output.
+  function parseModuleJson(raw) {
+    var text = String(raw || "").trim()
+    if (!text) return {}
+    var lines = text.split("\n")
+    try {
+      return JSON.parse(lines[lines.length - 1])
+    } catch (e) {
+      return { text: text }
+    }
+  }
+
   // Layout normalization shared by the bar host and the bar settings panel
   // so the two never drift. Entries are deep-cloned to decouple from the
   // input config; consumers can mutate without leaking back to shell.json.

shell/Ui/BarIndicator.qml

@@ -18,15 +18,7 @@ WidgetButton {
   readonly property bool inactiveRevealed: !effectiveActive && !!indicatorHost && indicatorHost.revealInactiveIndicators
 
   function extractData(raw) {
-    var text = String(raw || "").trim()
-    if (text === "") return {}
-
-    var lines = text.split("\n")
-    try {
-      return JSON.parse(lines[lines.length - 1])
-    } catch (error) {
-      return { text: text }
-    }
+    return Util.parseModuleJson(raw)
   }
 
   function syncIndicatorOpacity() {

shell/plugins/bar/Bar.qml

@@ -751,7 +751,7 @@ Item {
     }
 
     function update(raw) {
-      var data = root.parseModuleJson(raw)
+      var data = Util.parseModuleJson(raw)
       var klass = data.class || data.alt || ""
 
       outputText = data.text || String(raw || "").trim()