modules: Fix ModuleProfile::is_default method

The previously used `modulemd_profile_is_default` gets the information
about defaults from modulemd-packager yaml document, which is available
when building a module, but doesn't work for modules after building.

libdnf5/module/module_profile.cpp

@@ -64,7 +64,7 @@ bool ModuleProfile::is_default() const {
     if (!profile) {
         return {};
     }
-    return modulemd_profile_is_default(profile);
+    return is_default_profile;
 }