Revert "Flatpak: Bundle meson"

This reverts commit c672bf138c.

Meson 0.48+ is on the runtime now and this is no longer needed

build-aux/flatpak/org.gnome.Evince.json

@@ -46,20 +46,6 @@
         "*.a"
     ],
     "modules": [
-        {
-            "name" : "meson",
-            "buildsystem" : "simple",
-            "build-commands" : [
-                "python3 setup.py install --prefix=/app"
-            ],
-            "sources" : [
-                {
-                    "type" : "git",
-                    "url" : "https://github.com/mesonbuild/meson.git",
-                    "tag" : "0.48.0"
-                }
-            ]
-        },
         {
             "name": "openjpeg",
             "buildsystem": "cmake-ninja",