Fix public version check (#1203)

Summary:
Relied too much on TSC and not enough on my brain.

![image](https://user-images.githubusercontent.com/9906/83158023-2f0ff880-a0fc-11ea-8f1b-bff89ec7934a.png)
Pull Request resolved: https://github.com/facebook/flipper/pull/1203

Test Plan:
![Screenshot 2020-05-28 15 51 49](https://user-images.githubusercontent.com/9906/83158051-38996080-a0fc-11ea-8e59-9bb6cd88d832.png)

Endpoint is getting hit on startup now for public builds.

Reviewed By: mweststrate

Differential Revision: D21764325

Pulled By: passy

fbshipit-source-id: 771c4e430717f4eae5eab36f279ca3eff9e9bcf7

desktop/app/src/chrome/UpdateIndicator.tsx

@@ -19,7 +19,7 @@ import {reportPlatformFailures} from '../utils/metrics';
 import React from 'react';
 import {shell} from 'electron';
 import config from '../utils/processConfig';
-import isFBBuild from '../fb-stubs/config';
+import fbConfig from '../fb-stubs/config';
 
 const Container = styled(FlexRow)({
   alignItems: 'center',
@@ -95,7 +95,7 @@ export default class UpdateIndicator extends React.PureComponent<Props, State> {
   }
 
   componentDidMount() {
-    if (isProduction() && (config().launcherEnabled || !isFBBuild)) {
+    if (isProduction() && (config().launcherEnabled || !fbConfig.isFBBuild)) {
       reportPlatformFailures(
         checkForUpdate(this.props.version).then((res) => {
           if (res.kind === 'error') {