Fix compatibility break for CI

(cherry picked from commit 38e517b98b537303a153bdefba2c3f750ce289ea)

.github/actions/setup-godot-cpp/action.yml

@@ -23,6 +23,7 @@ inputs:
     default: r23c
     description: Android NDK version.
   buildtool:
+    default: scons
     description: scons or cmake
   scons-version:
     default: 4.4.0