Fix issues with WidgetImageView skeleton placeholder

The 'automagic' skeleton addition caused two issues:
- Misplaced icon in section switches (openhab#3773)
  This was caused by constraints in the widget's ConstraintLayout
  referencing the WidgetImageView's ID, which was no longer present
  after replacing it by the SkeletonLayout
- Skeleton and image shown at the same time (mentioned in openhab#3786)
  This was caused by WidgetAdapter and SkeletonLayout both
  simultaneously modifying the visibility flag of the WidgetImageView,
  again caused by silent replacement of WidgetImageView by
  SkeletonLayout

Fix both issues by changing the approach: Instead of silently replacing
the view, make WidgetImageView inherit from SkeletonLayout and make it
redirect external calls to an internal ImageView instance.

Fixes openhab#3773, openhab#3786

Signed-off-by: Danny Baumann <[email protected]>

mobile/src/main/java/org/openhab/habdroid/ui/WidgetAdapter.kt

@@ -1037,11 +1037,10 @@ class WidgetAdapter(
 
             // Make sure images fit into the content frame by scaling
             // them at max 90% of the available height
-            if (initData.parent.height > 0) {
-                imageView.maxHeight = (0.9f * initData.parent.height).roundToInt()
-            } else {
-                imageView.maxHeight = Integer.MAX_VALUE
-            }
+            imageView.setMaxHeight(when {
+                initData.parent.height > 0 -> (0.9f * initData.parent.height).roundToInt()
+                else -> Integer.MAX_VALUE
+            })
             imageView.setImageScalingType(prefs.getImageWidgetScalingType())
 
             if (value != null && value.matches("data:image/.*;base64,.*".toRegex())) {