[Admin dashboard] Show billing detail for teams and users

[jldec]

Teams and users with billing enabled need a "Billing" indicator in the team detail page, similar to the "Plan" indicator for Users.

The values for this should be one of the following:

• Professional or Unleashed (if team is on a Chargebee team-billing plan)
• Usage-based (if team is on a Stripe UBP subscription)

Related to #14367

[gtsiolis]

@jldec Shall we also drop the BillingMode column?

User with chargebee	User with usage-based

[jldec]

Shall we also drop the BillingMode column?

@gtsiolis - no - the BillingMode is true for UBP-enabled teams (feature flagged), even if they have not yet configured any team-level billing.