Support IAM profile authentication for Redshift

I am trying to use sqlmesh over a Redshift dbt project with IAM authentication in the connection profile

```
sqlmesh ui
Error: 1 validation error for RedshiftConfig
password
  Field required [type=missing, input_value={'name': 'dev', 'profile_...True, 'database': 'dev'}, input_type=dict]
    For further information visit https://errors.pydantic.dev/2.6/v/missing
```