Fix dag randering for taskflow + DbtTaskGroup combo (#1360)

## Description
I believe the deepcopy results in two separate DAG objects—the original
object and its deepcopy and the task is referencing to both objects
causing failure
```
airflow.exceptions.AirflowException: Tried to set relationships between tasks in more than one DAG: {<DAG: DAG_NAME>, <DAG: DAG_NAME>}
``` 

<img width="1681" alt="Screenshot 2024-12-03 at 2 30 23 AM"
src="https://github.com/user-attachments/assets/93859f4b-84d1-4e60-87a7-25a1b750a8e3">

DAG Code

```python
from datetime import datetime

from airflow.decorators import task, dag
from cosmos import DbtTaskGroup, ProjectConfig
from include.constants import jaffle_shop_path, venv_execution_config, manifest_path
from include.profiles import airflow_db

@task(task_id="build_partial_dbt_env_vars_operator")
def build_partial_dbt_env():
    # some code
    # This return is for demonstration purposes only
    return {
        "ENV_VAR_NAME": "value",
        "ENV_VAR_NAME_2": False
    }


# partial_dbt_env = build_partial_dbt_env()



@dag(
    schedule_interval="@daily",
    start_date=datetime(2023, 1, 1),
    catchup=False,
    tags=["simple"],
)
def simple_task_group1() -> None:
    DbtTaskGroup(
        group_id="transform_task_group",
        project_config=ProjectConfig(
        dbt_project_path=jaffle_shop_path,
        manifest_path=manifest_path,
        env_vars=build_partial_dbt_env()
    ),
        profile_config=airflow_db,
        execution_config=venv_execution_config,
    )

simple_task_group1()
#partial_dbt_env >> transform_task_group
``` 

<!-- Add a brief but complete description of the change. -->

## Related Issue(s)

closes: #1218

## Breaking Change?

<!-- If this introduces a breaking change, specify that here. -->

## 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

cosmos/converter.py

@@ -229,8 +229,8 @@ def __init__(
 
         validate_changed_config_paths(execution_config, project_config, render_config)
 
-        env_vars = copy.deepcopy(project_config.env_vars or operator_args.get("env"))
-        dbt_vars = copy.deepcopy(project_config.dbt_vars or operator_args.get("vars"))
+        env_vars = project_config.env_vars or operator_args.get("env")
+        dbt_vars = project_config.dbt_vars or operator_args.get("vars")
 
         if execution_config.execution_mode != ExecutionMode.VIRTUALENV and execution_config.virtualenv_dir is not None:
             logger.warning(

dev/dags/example_taskflow.py

@@ -0,0 +1,48 @@
+import os
+from datetime import datetime
+from pathlib import Path
+
+from airflow.decorators import dag, task
+
+from cosmos import DbtTaskGroup, ProfileConfig, ProjectConfig
+from cosmos.profiles import PostgresUserPasswordProfileMapping
+
+DEFAULT_DBT_ROOT_PATH = Path(__file__).parent / "dbt"
+DBT_ROOT_PATH = Path(os.getenv("DBT_ROOT_PATH", DEFAULT_DBT_ROOT_PATH))
+
+
+profile_config = ProfileConfig(
+    profile_name="default",
+    target_name="dev",
+    profile_mapping=PostgresUserPasswordProfileMapping(
+        conn_id="example_conn",
+        profile_args={"schema": "public"},
+        disable_event_tracking=True,
+    ),
+)
+
+
+@task(task_id="build_partial_dbt_env_vars_operator")
+def build_partial_dbt_env():
+    return {"ENV_VAR_NAME": "value", "ENV_VAR_NAME_2": False}
+
+
+@dag(
+    schedule_interval="@daily",
+    start_date=datetime(2024, 1, 1),
+    catchup=False,
+)
+def example_taskflow() -> None:
+    DbtTaskGroup(
+        group_id="transform_task_group",
+        project_config=ProjectConfig(
+            dbt_project_path=DBT_ROOT_PATH / "jaffle_shop",
+            manifest_path=DBT_ROOT_PATH / "jaffle_shop" / "target" / "manifest.json",
+            env_vars=build_partial_dbt_env(),
+        ),
+        profile_config=profile_config,
+        operator_args={"install_deps": True},
+    )
+
+
+example_taskflow()