Fix a11y read-twice bug

Also remove a hardcoded string

Test: manual with talkback
Fixes: 133731969
Change-Id: I0effe046fd6edddd109335a6dd7fa6b732587d64

packages/SystemUI/src/com/android/systemui/statusbar/notification/row/ChannelEditorDialogController.kt

@@ -223,6 +223,8 @@ class ChannelEditorDialogController @Inject constructor(
         dialog = Dialog(context)
 
         dialog.window?.requestFeature(Window.FEATURE_NO_TITLE)
+        // Prevent a11y readers from reading the first element in the dialog twice
+        dialog.setTitle("\u00A0")
         dialog.apply {
             setContentView(R.layout.notif_half_shelf)
             setCanceledOnTouchOutside(true)

packages/SystemUI/src/com/android/systemui/statusbar/notification/row/ChannelEditorListView.kt

@@ -143,7 +143,7 @@ class ChannelRow(c: Context, attrs: AttributeSet) : LinearLayout(c, attrs) {
     private fun updateViews() {
         val nc = channel ?: return
 
-        channelName.text = nc.name ?: "(missing)"
+        channelName.text = nc.name ?: ""
 
         nc.group?.let { groupId ->
             channelDescription.text = controller.groupNameForId(groupId)