When in billing mode "chargebee", we should not be checking the usage-based spending limit

[jankeromnes]

Bug description

When in billing mode "chargebee", we should not be checking/enforcing the usage-based spending limit.

However, it seems that if your team has a cost center, the spending limit is still being checked even when in mode "chargebee", which can prevent starting new workspaces (see internal incident).

Steps to reproduce

1. Set a low spending limit for your team (e.g. by enabling usage-based and setting a spending limit of 1)
2. Go back to Chargebee mode (e.g. by disabling usage-based and purchasing a Chargebee team plan)
3. Try to start a workspace

Workspace affected

No response

Expected behavior

Expected behavior: The workspace starts

Actual behavior: The workspace fails to start because you've reached your team's spending limit

Example repository

No response

Anything else?

No response