)

Prompt the user if they want to re-authenticate if they run
`coder login` when already authenticated.

Does not apply if they provided a token via flag or ENV
variable. A new token should be generated an stored in that situation
unless the `--use-token-as-session` flag was also used.

fix(cli): prompt user on login attempt with invalid ENV token

Fixes issue where if invalid token was set as ENV
variable a user would be unable to login until the ENV
variable was cleared.

User will now be informed that the token is invalid and
prompted to login normally.

cliui should return nil when returning cliui.Canceled (CTRL-C) and
return error others

fix nits

I made an incorrect assumption, we can check if
a flag/env token is valid on login and create a new
token if the provided one is invalid.

However, on subsequent requests the invalid ENV token
will still take priority over the valid token stored
on disk. Therefore, this behavior does not work.