Fix a bug where Analytics is always enabled even Analytics is set to "Enable in JavaScript"

[dhei]

Issue: When Analytics is set to "Enable in JavaScript" in the following question in react-native link:

For the [platform] app, should user tracking be enabled automatically ? (Use arrow keys)
          Enable Automatically
        > Enable in JavaScript

Analytics is supposed to remain disabled until await Analytics.setEnabled(true); called in JavaScript code. But Analytics is not disabled in this case. This issue exists in both iOS and Android. It is not affecting other services (e.g. Crashes service).

Root cause: Analytics.setEnabled(false); should not be called before Analytics service is started.

Fix: Start Analytics before calling .setEnabled(false).

[msftclas]

@dhei,
Thanks for your contribution as a Microsoft full-time employee or intern. You do not need to sign a CLA.
Thanks,
Microsoft Pull Request Bot