[core] Do not require authed user for sanity start

[rexxars]

Type of change (check at least one)

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation (fix or update to documentation)
• Maintenance
• Other, please describe:

Does this change require a documentation update? (Check one)

• Yes
• No

Current behavior

When you run sanity start without being authenticated in the CLI, it'll tell you:

Error: You must login first - run "sanity login"

...which is weird, as there are no API interactions to start up a development server

Description

This PR passes a flag to the client wrapper telling it that the command does not require an authenticated user.

Note for release

• Fixed sanity start giving error if CLI had no locally authenticated user

Checklist

• I have read the Contributing Guidelines
• The PR title includes a link to the relevant issue
• The PR title is appropriately formatted: [some-package] PR title (#123)
• The code is linted
• The test suite is passing
• Corresponding changes to the documentation have been made

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[kmelve]

LGTM!