Update NovaShell version to c6454d3220 (#593)

user/dadk/config/nova_shell-0.1.0.dadk

@@ -6,7 +6,7 @@
     "BuildFromSource": {
       "Git": {
         "url": "https://git.mirrors.dragonos.org.cn/DragonOS-Community/NovaShell.git",
-        "revision": "473d5c403c"
+        "revision": "c6454d3220"
       }
     }
   },