Actually set default brandColor in SoapboxMount

app/soapbox/containers/soapbox.js

@@ -48,7 +48,7 @@ const mapStateToProps = (state) => {
     dyslexicFont: settings.get('dyslexicFont'),
     demetricator: settings.get('demetricator'),
     locale: settings.get('locale'),
-    themeCss: generateThemeCss(state.getIn(['soapbox', 'brandColor'])),
+    themeCss: generateThemeCss(state.getIn(['soapbox', 'brandColor'], '#0482d8')), // Azure default
     themeMode: settings.get('themeMode'),
   };
 };

app/soapbox/reducers/soapbox.js

@@ -1,14 +1,12 @@
 import { SOAPBOX_CONFIG_IMPORT } from '../actions/soapbox';
 import { Map as ImmutableMap, fromJS } from 'immutable';
 
-const initialState = ImmutableMap({
-  brandColor: '#0482d8', // Azure
-});
+const initialState = ImmutableMap();
 
 export default function soapbox(state = initialState, action) {
   switch(action.type) {
   case SOAPBOX_CONFIG_IMPORT:
-    return initialState.merge(ImmutableMap(fromJS(action.soapboxConfig)));
+    return ImmutableMap(fromJS(action.soapboxConfig));
   default:
     return state;
   }