Fix: Prevent RecyclerView from resetting scroll position after returning from preview (#5873) (#5880)

Resolved an issue where RecyclerView would incorrectly scroll to the top after exiting fullscreen preview. Adjusted scroll behavior to maintain position unless actioned images are filtered. Implemented observer logic adjustments to handle dataset updates more efficiently.

Co-authored-by: Nicolas Raoul <[email protected]>

Author: lzhan0121

app/src/main/java/fr/free/nrw/commons/customselector/ui/selector/ImageFragment.kt

@@ -285,9 +285,11 @@ class ImageFragment :
                 imageAdapter.notifyDataSetChanged()
                 selectorRV?.let {
                     it.visibility = View.VISIBLE
-                    lastItemId?.let { pos ->
-                        (it.layoutManager as GridLayoutManager)
-                            .scrollToPosition(ImageHelper.getIndexFromId(filteredImages, pos))
+                    if (switch?.isChecked == false) {
+                        lastItemId?.let { pos ->
+                            (it.layoutManager as GridLayoutManager)
+                                .scrollToPosition(ImageHelper.getIndexFromId(filteredImages, pos))
+                        }
                     }
                 }
             } else {