cleanup: Use deepUnpack() intead of deep_unpack()

deep_unpack() is just a backwards compability alias for deepUnpack()[1].
The new name makes it more clear that this is not a C function, start to
use it.

[1] 13e662a29d

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2416>

js/ui/shellDBus.js

@@ -115,7 +115,7 @@ var GnomeShell = class {
         }
 
         for (let param in params)
-            params[param] = params[param].deep_unpack();
+            params[param] = params[param].deepUnpack();
 
         const {
             connector,