[release/8.0] Default to browser token auth in dashboard standalone

[JamesNK]

Backports #3427

Customer Impact

This PR changes the dashboard to default frontend auth to browser token. Previously, the dashboard would throw an error if no auth was configured unless suppressed. Providing a good default instead of an error makes using the standalone dashboard a nicer experience when getting started and it offers a secure default rather than forcing users to explicitly opt-out of auth altogether.

While making these changes, I tested the standalone dashboard much more heavily than before and found some related bugs. They're also fixed in this PR.

This PR:

• Changes dashboard to default to browser token auth in the frontend, and unsecured in OTLP endpoint
• Displays a warning about the unsecured OTLP endpoint in the console and in the UI with a message bar
• Fixes the browser token being generated multiple times
• Fixes the addresses written to the console to be the first address (matches host) instead of the last address
• Fixes the addresses written to the console to be localhost if localhost is specified.

Demo:

Testing

Manual and unit tests.

Risk

Low-Medium. Changing the default auth mode is a simple change. There is some new UI (message bar) for warning about unsecured OTLP endpoint.

Regression?

No

Microsoft Reviewers: Open in CodeFlow