Improve the error message when trying to integrate the Organization with G Suite

When trying to integrate G Suite to the Organization, the user may be prompted with below error message:

"We could not connect your G Suite Instance"
The G Suite instance you are trying to connect has already been connected to an organization.

One of the possible causes of this issue, is if a domain which is verified on G Suite (and therefore will be part of the sync), is already verified to the Atlassian Org (either via DNS or HTTPS).

According to our documentation, this is expected:
Because you verify your domain as part of your integration with Google, you can't verify your domain from your site. If you want to verify your domain, you'll need to disconnect the G Suite integration.

However, the error message is not effective in pointing this.

That said, it would be really useful if the error message indicates that the integration is not possible because a domain which would be part of the sync is already verified at Atlassian.