meson: Workaround python 3.12 warning

When we are building againt python 3.12, ignore redundant-decls warning
that will come from the python headers.

```
/usr/include/python3.12/longobject.h:10:26: warning: redundant redeclaration of ‘PyLong_Type’ [-Wredundant-decls]
   10 | PyAPI_DATA(PyTypeObject) PyLong_Type;
      |                          ^~~~~~~~~~~
```

python/cpython#106560

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/5541>

subprojects/gst-editing-services/meson.build

@@ -156,9 +156,11 @@ elif build_gir
   if python.found()
     # Workaround for https://github.com/mesonbuild/meson/issues/5629
     pythonver = python.language_version()
-    python_dep = dependency('python-@0@-embed'.format(pythonver), version: '>=3', required: false)
+    python_dep = dependency('python-@0@-embed'.format(pythonver), version: '>=3',
+                            required: false, include_type: 'system')
     if not python_dep.found()
-      python_dep = python.dependency(required : get_option('python'))
+      python_dep = python.dependency(required : get_option('python'),
+                                     include_type: 'system')
     endif
   else
     python_dep = dependency('', required: false)