Improve test and freshness on_warning_callback

[pankajastro]

Cosmos, at the moment, triggers on_warning_callback on dbt test even if it sees a "warn" message in logs. I believe we can improve our log parsing to avoid it and control it better. The parsing code is at https://github.com/astronomer/astronomer-cosmos/blob/main/cosmos/dbt/parser/output.py

Example

Test warn

1 of 1 WARN 1 unique_stg_green_taxi_color ...................................... [WARN 1 in 2.14s]

freshness warn

 1 of 1 WARN freshness of postgres_db.raw_orders ................................ [WARN in 0.02s]

[github-actions]

This issue is stale because it has been open for 30 days with no activity.