Merge branch 'fix-themes-select' into 'develop'

Fix theme select not working

See merge request pleroma/pleroma-fe!1393

src/modules/config.js

@@ -94,7 +94,8 @@ const config = {
       const { defaultConfig } = rootGetters
       return {
         ...defaultConfig,
-        ...state
+        // Do not override with undefined
+        ...Object.fromEntries(Object.entries(state).filter(([k, v]) => v !== undefined))
       }
     }
   },