[FIX] mass_mailing: should not land on top

Before this commit:

When the page is expanded and try to add any block with an image, try to change
the image using replace button. It lands the user at the top of the page instead
of staying image place.

After this commit:

The user will stay at the image place after clicking on replace button.

Task-2753302

closes odoo/odoo#97266

X-original-commit: da4fdd90622b1f6ba2e45e717fcb4fdde09033af
Signed-off-by: David Monjoie (dmo) <dmo@odoo.com>

addons/mass_mailing/static/src/js/mailing_mailing_view_form_full_width.js

@@ -108,7 +108,11 @@ const MassMailingFullWidthFormController = FormController.extend({
         } else {
             const ref = $iframeDoc.find('#iframe_target')[0];
             if (ref) {
-                this.$iframe.height(Math.max(ref.scrollHeight + VERTICAL_OFFSET, minHeight));
+                this.$iframe.css({
+                    height: this._isFullScreen()
+                        ? $(window).height()
+                        : Math.max(ref.scrollHeight + VERTICAL_OFFSET, minHeight),
+                });
             }
         }
     },
@@ -126,7 +130,6 @@ const MassMailingFullWidthFormController = FormController.extend({
         const isFullscreen =  this._isFullScreen();
         if (isFullscreen) {
             $sidebar.height(windowHeight);
-            this.$iframe.height(windowHeight);
             $sidebar.css({
                 top: '',
                 bottom: '',