rn: fix overriding user-selected server URL

Fixes: https://github.com/jitsi/jitsi-meet/issues/7373

react/features/app/components/App.native.js

 
 import { setColorScheme } from '../../base/color-scheme';
 import { DialogContainer } from '../../base/dialog';
-import { CALL_INTEGRATION_ENABLED, SERVER_URL_CHANGE_ENABLED, updateFlags } from '../../base/flags';
+import { updateFlags } from '../../base/flags/actions';
+import { CALL_INTEGRATION_ENABLED, SERVER_URL_CHANGE_ENABLED } from '../../base/flags/constants';
+import { getFeatureFlag } from '../../base/flags/functions';
 import { Platform } from '../../base/react';
 import { DimensionsDetector, clientResized } from '../../base/responsive-ui';
 import { updateSettings } from '../../base/settings';
         super.componentDidMount();
 
         this._init.then(() => {
+            const { dispatch, getState } = this.state.store;
+
             // We set these early enough so then we avoid any unnecessary re-renders.
-            const { dispatch } = this.state.store;
+            dispatch(setColorScheme(this.props.colorScheme));
+            dispatch(updateFlags(this.props.flags));
 
             // Check if serverURL is configured externally and not allowed to change.
-            const serverURLChangeEnabled = this.props.flags[SERVER_URL_CHANGE_ENABLED];
+            const serverURLChangeEnabled = getFeatureFlag(getState(), SERVER_URL_CHANGE_ENABLED, true);
 
             if (!serverURLChangeEnabled) {
                 // As serverURL is provided externally, so we push it to settings.
                 }
             }
 
-            dispatch(setColorScheme(this.props.colorScheme));
-            dispatch(updateFlags(this.props.flags));
             dispatch(updateSettings(this.props.userInfo || {}));
 
             // Update settings with feature-flag.