logLevel is not honored by instance

For React SDK. `logLevel` is not honored when setting up the instance.

```
const optimizely = optimizelySDK.createInstance({
  sdkKey: OPTIMIZELY_SDK_KEY,
  // Log Level settings [0, 1, 2, 3, 4]
  // https://github.com/optimizely/node-sdk/blob/master/lib/utils/enums/index.js#L20-L26
  logLevel: 0
})
```

Still displays console logs when running.