Fix entity-based lookup in html & scriptlet filtering

Entity-based filters where not properly looked-up if
they used subdomains. Example:

- `example.*##^script` => ok

- `www.example.*##^script` => failed on `https://www.example.com/`

src/js/html-filtering.js

@@ -356,7 +356,7 @@
         );
         if ( details.entity !== '' ) {
             filterDB.retrieve(
-                `${hostname.slice(0, -details.domain)}${details.entity}`,
+                `${hostname.slice(0, -details.domain.length)}${details.entity}`,
                 [ plains, exceptions, procedurals, exceptions ]
             );
         }

src/js/scriptlet-filtering.js

@@ -369,7 +369,7 @@
         );
         if ( request.entity !== '' ) {
             scriptletDB.retrieve(
-                `${hostname.slice(0, -request.domain)}${request.entity}`,
+                `${hostname.slice(0, -request.domain.length)}${request.entity}`,
                 [ scriptlets, exceptions ]
             );
         }