Get Auth Token in an Async way to resolve dashboard Oops error when idle

[mechaffin]

Type of change?

• [x] Bug fix
• [ ] New feature
• [ ] Enhancement
• [ ] Breaking change (breaks backward compatibility)

Description, Context, Motivation

Change handling of getting the auth token to be async. This should fix the "oops" errors that occur on the dashboard when left idle for a long period of time (and the token times out and gets refreshed).

Addresses: https://github.com/Azure/pcs-remote-monitoring-webui/issues/1079

Checklist:

• [x] All tests passed
• [x] The code follows the code style and conventions of this project
• [ ] The change requires a change to the documentation
• [ ] I have updated the documentation accordingly

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This change is