getViewer was building a new HTTP client from scratch, losing
AppVersion and InvokingAgent from the plain client already passed
into AuthFlow. Reuse the existing client by shallow-copying it and
wrapping its transport with AddAuthTokenHeader for the new token.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
IsEnterprise currently returns `true` when `IsTenancy` returns true. We
prefer that this behavior is orthogonal. This commit adds failing tests to
the instances where IsEnterprise should not behave the same as IsTenancy.
These test cases are expected to pass with the inclusion of the coming
improvements to go-gh to handle the orthogonality of IsEnterprise and
IsTenancy.
