flatpak: Cleanup unwanted static libraries

The CEF static library in special is gigantic (50MB+) and
was significantly increasing the bundle size.

CI/flatpak/com.obsproject.Studio.json

@@ -140,7 +140,8 @@
       "no-autogen": true,
       "cleanup": [
         "/bin",
-        "/include"
+        "/include",
+        "*.a"
       ],
       "sources": [
         {
@@ -236,6 +237,7 @@
         "cp -R ./libcef_dll_wrapper/libcef_dll_wrapper.a /app/cef/libcef_dll_wrapper"
       ],
       "cleanup": [
+        "*.a",
         "./*"
       ],
       "sources": [