[FIX] website: enable the use of the save option only on snippets

Steps to reproduce the bug:
- Add a "Table of Content" on the website.
- Try to save a "Block" of the table.
- 14.0: you get an error message.
- 15.0: it keeps loading forever.
- 16.0: you get a white page.

Users should not have the possibility to save part of a snippet. The
goal of this commit is to ensure that the save option applies on a
snippet. If it is the case, the user has the possibility to save it. If
not, the user does not have the opportunity to save it.

opw-3056913

closes odoo/odoo#108002

X-original-commit: 5f28c7d9a04c46d570b13766eaaa90e755008623
Signed-off-by: Quentin Smetz (qsm) <qsm@odoo.com>

addons/website/views/snippets/snippets.xml

@@ -644,7 +644,7 @@
         data-drop-in=".content, nav"/>
 
     <div data-js="SnippetSave"
-        t-attf-data-selector="#{so_snippet_addition_selector}, #{so_content_addition_selector}, .s_popup"
+        data-selector="[data-snippet]"
         data-exclude=".o_no_save">
         <we-button class="fa fa-fw fa-save o_we_link o_we_hover_warning"
                    title="Save the block to use it elsewhere"