Render ephemeral type DBT model & no freshness DBT source with test as EmptyOperator

[okayhooni]

Description

• dbt models with ephemeral materialization type that serve only as CTEs should not be rendered as DbtRunOperator tasks, as they unnecessarily occupy Airflow worker slots, even for a short period.
• Updated the logic to render these ephemeral models as EmptyOperator tasks instead, ensuring they are processed quickly by the Airflow scheduler without being assigned to an Airflow worker.
• Similarly, DBT source nodes without a freshness check but with downstream tests are rendered as EmptyOperator to avoid unnecessary worker slot resource consumption.

Breaking Change?

No

Checklist

• I have made corresponding changes to the documentation (if required)
• I have added tests that prove my fix is effective or that my feature works

[netlify]

✅ Deploy Preview for sunny-pastelito-5ecb04 canceled.

Name	Link
🔨 Latest commit	32b15b9
🔍 Latest deploy log	https://app.netlify.com/sites/sunny-pastelito-5ecb04/deploys/67dab105e5ffc20008e00547

[codecov]

Codecov Report

Attention: Patch coverage is 92.30769% with 1 line in your changes missing coverage. Please review.

Project coverage is 97.41%. Comparing base (43b5400) to head (32b15b9).
Report is 25 commits behind head on main.

Files with missing lines	Patch %	Lines
cosmos/airflow/graph.py	88.88%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1625      +/-   ##
==========================================
- Coverage   97.43%   97.41%   -0.02%     
==========================================
  Files          80       80              
  Lines        4950     4957       +7     
==========================================
+ Hits         4823     4829       +6     
- Misses        127      128       +1     

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[github-actions]

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