Typo in ad 1-on-1-voice-calling

### This issue is for a:
```
- [x] bug report -> please search issues before submitting
- [ ] feature request
- [ ] documentation issue or request
- [ ] regression (a behavior that used to work and stopped in a new release)
```

### Minimal steps to reproduce
Hi guys I have a found a typo in your webpack configuration that is blocking the app from runing:

https://github.com/Azure-Samples/communication-services-javascript-quickstarts/blob/60245b4cb793ea4cd918e633dbeb4a3c5beec340/add-1-on-1-video-calling/webpack.config.js#L19

### Any log messages given by the failure
> Webpack error when tyrint to run the app

`ERROR in unable to locate 'communication-services-javascript-quickstarts/add-1-on-1-video-calling/index.thml' glob`

### Expected/desired behavior
> Expect to run the app successfully.

Open add-1-on-1-video-calling/webpack.config.js at line 19 and compare the referenced path with the existing app entry file. Start by checking the reported Webpack error, then run the app to confirm the configuration resolves the entry file and the sample starts successfully.

Written by the indexing model from the issue text.