[FIX] web_editor: correctly position loading element

In the Website Builder, when clicking on the THEME tab, and clicking on
the "Switch theme" button, the loader behind the dialog was not placed
correctly.

After [1] moved the manipulators inside the iframe, the css rule for the
loading elements was not updated to remove its right value, used to
position the loading element next to the right panel.

[1]: https://github.com/odoo/odoo/commit/872bb20b3ac08cf82613e15e6634a2e7593ccf7a

X-original-commit: 106a5a56a96090ae4adfd9e7b3ea2f93d69dca22
Part-of: odoo/odoo#103562

addons/web_editor/static/src/scss/wysiwyg_snippets.scss

@@ -2508,7 +2508,6 @@ we-button:hover .o_we_shape_animated_label > span {
     // be over the content being reloaded (with a covering similar to the editor
     // overlay covering).
     position: fixed;
-    right: $o-we-sidebar-width;
 }
 
 .o_we_force_no_transition {