Meta: Remove base64 utility from the GN build

Meta/gn/secondary/BUILD.gn

@@ -6,7 +6,6 @@ group("default") {
     "//Meta/Lagom/Tools/CodeGenerators/IPCCompiler",
     "//Tests",
     "//Userland/Libraries/LibWeb",
-    "//Userland/Utilities:base64",
     "//Userland/Utilities:js",
   ]
   testonly = true

Meta/gn/secondary/Userland/Utilities/BUILD.gn

@@ -1,13 +1,3 @@
-executable("base64") {
-  sources = [ "base64.cpp" ]
-  include_dirs = [ "//Userland/Libraries" ]
-  deps = [
-    "//AK",
-    "//Userland/Libraries/LibCore",
-    "//Userland/Libraries/LibMain",
-  ]
-}
-
 executable("js") {
   sources = [ "js.cpp" ]
   include_dirs = [ "//Userland/Libraries" ]