build: Change dependency order building libmutter-test introspection

The order of dependencies influences the order of -L arguments to gcc/ld,
we should put our private library first, so that introspection prefers
looking up libraries in private paths than public ones.

This could bring problems in API updates of the libmutter-test library,
since introspection would still prefer the old installed one.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2826>

src/tests/meson.build

@@ -90,9 +90,9 @@ if have_introspection
       libmutter_gir[0],
     ],
     dependencies: [
-      mutter_deps,
-      libmutter_dep,
       libmutter_test_dep,
+      libmutter_dep,
+      mutter_deps,
     ],
     extra_args: mutter_c_args + introspection_args,
     install_dir_gir: pkglibdir,