qml, desktop: Fix custom datadir doubleclick

This is a desktop-only (not mobile) workaround to disable doubleclick
on custom datadir which is on the StorageLocations.qml componennt.

Double-clicking was causing the file dialog to get open but losing
focus and moving to the background, bringing upfront the main
window which was useless because the file dialog is modal.

src/qml/components/StorageLocations.qml

@@ -29,7 +29,28 @@ ColumnLayout {
         ButtonGroup.group: group
         text: qsTr("Custom")
         description: qsTr("Choose the directory and storage device.")
-        onClicked: fileDialog.open()
+        onClicked: {
+            if (AppMode.isDesktop) {
+                if (!singleClickTimer.running) {
+                    // Start the timer if it's not already running
+                    singleClickTimer.start();
+                } else {
+                    // If the timer is running, it's a double-click
+                    singleClickTimer.stop();
+                }
+            } else {
+                fileDialog.open()
+            }
+        }
+        Timer {
+            id: singleClickTimer
+            interval: 50
+            onTriggered: {
+                // If the timer times out, it's a single-click
+                fileDialog.open()
+            }
+            repeat: false // No need to repeat the timer
+        }
     }
     FileDialog {
         id: fileDialog