Duplicate prefix shown for private spaces warning message

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Do you want to request a feature or report a bug?

Bug

What is the current behavior?

$ h run -a <some private spaces app> bash
Running bash on ⬢ <some private spaces app>... ⣯
 ›   Warning: Warning: Dynos can take up to a few minutes to be provisioned in Private Spaces.

ie: The warning message has a duplicate prefix: Warning: Warning:

What is the expected behavior?

For the warning message to start with Warning: not Warning: Warning:.

Using DEBUG=* the API is returning:

  http   warning-message: 'Warning: Dynos can take up to a few minutes to be provisioned in Private Spaces.'

And then I'm presuming heroku-cli-util is prefixing it further, due to the use of .warn() here? https://github.com/heroku/heroku-cli-util/blob/3807dd6968ca039130d8ff2f9a48610deab3ee46/lib/command.js#L64-L65

It seems that either the API responses need to not include the "Warning:" prefix, or else the CLI needs to trim such prefixes first if it's going to add it's own.

The API wording itself comes from: https://github.com/heroku/api/blob/2af59cdad427b7b9b54327422df256518ffb7065/config/locales/en.yml#L649

However, there are several other message constants that use the "Warning:" prefix, which might need fixing too? https://github.com/search?q=repo%3Aheroku%2Fapi+%22Warning%3A%22+path%3A%2F%5Econfig%5C%2F%2F&type=code

heroku / cli