[FIX] web_editor: fix image deletion and replacement

Deleting/replacing an image through summernote gave unexpected results.
As modifiying the related function may be tricky, this commit instead
wrap them to solve the specific erratic behavior: if the range is in/
matches an image, then simply remove the image and move the cursor to
its previous location.

addons/web_editor/static/src/js/summernote.js

@@ -953,15 +953,21 @@ range.WrappedRange.prototype.deleteContents = function (towrite) {
         return this;
     }
 
-    var prevBP = dom.removeBetween(this.sc, this.so, this.ec, this.eo, towrite);
+    var r;
+    var image = this.isOnImg();
+    if (image) {
+        // If the range matches/is in an image, then the image is to be removed
+        // and the cursor moved to its previous position
+        var parentNode = image.parentNode;
+        var index = _.indexOf(parentNode.childNodes, image);
+        parentNode.removeChild(image);
+        r = new range.WrappedRange(parentNode, index, parentNode, index);
+    } else {
+        r = dom.removeBetween(this.sc, this.so, this.ec, this.eo, towrite);
+    }
 
-    $(dom.node(prevBP.sc)).trigger("click"); // trigger click to disable and reanable editor and image handler
-    return new range.WrappedRange(
-      prevBP.sc,
-      prevBP.so,
-      prevBP.ec,
-      prevBP.eo
-    );
+    $(dom.node(r.sc)).trigger("click"); // trigger click to disable and reanable editor and image handler
+    return new range.WrappedRange(r.sc, r.so, r.ec, r.eo);
 };
 range.WrappedRange.prototype.clean = function (mergeFilter, all) {
     var node = dom.node(this.sc === this.ec ? this.sc : this.commonAncestor());