Remove some irrelevant TODOs in task sdk (apache#56506)

Author: amoghrajesh

task-sdk/src/airflow/sdk/definitions/variable.py

@@ -44,7 +44,6 @@ class Variable:
     value: Any | None = None
     description: str | None = None
 
-    # TODO: Extend this definition for reading/writing variables without context
     @classmethod
     def get(cls, key: str, default: Any = NOTSET, deserialize_json: bool = False):
         from airflow.sdk.exceptions import AirflowRuntimeError, ErrorType

task-sdk/src/airflow/sdk/execution_time/context.py

@@ -207,9 +207,6 @@ async def _async_get_connection(conn_id: str) -> Connection:
     from airflow.sdk.execution_time.supervisor import ensure_secrets_backend_loaded
     from airflow.sdk.execution_time.task_runner import SUPERVISOR_COMMS
 
-    # TODO: check cache first
-    # enabled only if SecretCache.init() has been called first
-
     # Try secrets backends first using async wrapper
     backends = ensure_secrets_backend_loaded()
     for secrets_backend in backends: