[FIX] web_editor: link don't duplicate child text

If we applied a link eg. on:

```
<span>hello <b>world</b></span>
```

The system actually gets the "label": hello worldworld because there is
3 nodes:

 text node: hello
 element node: `<b>world</b>`
 text node: world

Also since "hello worldworld" is different than "hello world",
instead of just keeping existing nodes and adding the link, the system
would replace the selected range by:

 `<span><a>hello worldworld</a></span>'

instead of:

 `<span><a>hello </a><b><a>world</a></b></span>`

This commit ignores element nodes when creating a new link, since when
getting the label of the link from the selection, only the text nodes
insides the element nodes have any interest.

There was a second issue because if we had:

```
<i><a href="hello">world</a></i>!
```

and tried to put a link over "world!", the code would decide: "world" is
inside a link so we will just update that link.

Thus we would get:

```
<i><a href="hello">world!</a></i>!
```

instead of:

```
<i><a href="hello">world</a></i><a href="hello">!</a>
```

opw-1848351
closes #25187

addons/web_editor/static/lib/summernote/src/js/module/Editor.js

@@ -629,9 +629,9 @@ define([
       }
 
       var anchors = [];
-      // ODOO: adding this branch to modify existing anchor
+      // ODOO: adding this branch to modify existing anchor if it fully contains the range
       var ancestor_anchor = dom.ancestor(rng.sc, dom.isAnchor);
-      if(ancestor_anchor) {
+      if(ancestor_anchor && ancestor_anchor === dom.ancestor(rng.ec, dom.isAnchor)) {
           anchors.push($(ancestor_anchor).html(linkText).get(0));
       } else if (isTextChanged) {
         // Create a new link when text changed.

addons/web_editor/static/src/js/widgets.js

@@ -1025,6 +1025,8 @@ var LinkDialog = Dialog.extend({
                     if (dom.ancestor(nodes[i], dom.isImg)) {
                         this.data.images.push(dom.ancestor(nodes[i], dom.isImg));
                         text += '[IMG]';
+                    } else if (!is_link && nodes[i].nodeType === 1) {
+                        // just use text nodes from listBetween
                     } else if (!is_link && i===0) {
                         text += nodes[i].textContent.slice(so, Infinity);
                     } else if (!is_link && i===nodes.length-1) {