[FEATURE] Wise: allow user to set environment on the connection popup

**Is your feature request related to a problem? Please describe.**
On Wise connection popup, user only able to use the Production environment - which is not always suitable for users needed to test on their Sandbox environment: https://sandbox.transferwise.tech/

**Describe the solution you'd like**
On Wise connection popup, add a dropbox that allow user to select Production or Sandbox environment. For each option, the base_url should follows:
- `Sandbox Environment`: https://sandbox.transferwise.tech
- `Production Environment`: https://transferwise.tech