[REM] website: remove useless method

Was introduced with bae7e32e4b for `website_version` which doesn't exist
anymore.

task-2211013

addons/website/models/ir_http.py

@@ -244,7 +244,7 @@ class Http(models.AbstractModel):
             request.website.menu_id
         if page and (request.website.is_publisher() or page.is_visible):
             _, ext = os.path.splitext(req_page)
-            return request.render(page.get_view_identifier(), {
+            return request.render(page.view_id.id, {
                 'deletable': True,
                 'main_object': page,
             }, mimetype=_guess_mimetype(ext))

addons/website/models/website_page.py

@@ -58,10 +58,6 @@ class Page(models.Model):
 
         return most_specific_page == page_to_test
 
-    def get_view_identifier(self):
-        """ Get identifier of this page view that may be used to render it """
-        return self.view_id.id
-
     def get_page_properties(self):
         self.ensure_one()
         res = self.read([