Fix(sqlmesh_dbt): Allow global options to be specified in both top-level and subcommand positions

[erindru]

the dbt cli allows a certain set of "global" options to be defined both at top level (before a subcommand) and at the subcommand level.

This means that the following are equivalent and valid:

$ dbt --profile jaffle_shop list
$ dbt list --profile jaffle_shop

This PR refactors how options are captured by the sqlmesh_dbt CLI to ensure that sqlmesh_dbt supports this too