[azsdk-cli] tsp generate-authoring-plan requires interactive authentication on every run

Steps to reproduce: Run the CLI command `azsdk tsp generate-authoring-plan --request "what is typespec"`

Behavior: The CLI pops up an interactive browser authentication window to log in to the knowledge base service. This is expected for first run, but it appears to happen every time the command is run

Expected behavior: I assumed that the login would be cached and the authentication should read from the cache, so that multiple requests don't add auth toil.

FYI @chunyu3