remove N+1 db queries for team names

[steveahnahn]

Summary

Optimize multi-team executor resolution in the scheduler by batching dag_id -> team_name lookups and passing the resolved team_name into executor selection, eliminating per-task DB queries when core.multi_team=true.
With multi-team enabled, the scheduler can process many task instances per loop. Previously, team resolution could trigger repeated database lookups (effectively N queries for N task instances) when selecting executors. This PR reduces that overhead by resolving team names once per unique DAG ID and reusing the results.

• Adds a batched lookup helper to resolve team names for multiple DAG IDs in one query
• Preserves legacy behavior when core.multi_team=false (no additional queries / logic).
• Add test_multi_team_executor_to_tis_batch_optimization to assert _executor_to_tis() performs a single batched query and does not call _get_task_team_name().

[uranusjr]

Let’s split this to a separate = statement and then if executor is None, this is too long IMO.

[uranusjr]

Suggested change

	dag_id_to_team_name: dict[str, str | None] = {}
	if conf.getboolean("core", "multi_team"):
	unique_dag_ids = {ti.dag_id for ti in task_instances_without_heartbeats}
	dag_id_to_team_name = self._get_team_names_for_dag_ids(unique_dag_ids, session)
	if conf.getboolean("core", "multi_team"):
	unique_dag_ids = {ti.dag_id for ti in task_instances_without_heartbeats}
	dag_id_to_team_name = self._get_team_names_for_dag_ids(unique_dag_ids, session)
	else:
	dag_id_to_team_name = {}

[uranusjr]

A couple of minor suggestions, overrall logic is good to me.