Fix the order that tasks are displayed in Grid view

[bbovenzi]

The order that tasks are displayed in Grid view do not correlate with the order that the tasks would be expected to execute in the DAG. See example_bash_operator below:

We should update the task_group_to_tree function in views.py to better approximate the order that tasks would be run.

[ashb]

We've got this function already, so it might be as simple as using that?

airflow/airflow/models/dag.py

Lines 1716 to 1726 in 3849b4e

	def topological_sort(self, include_subdag_tasks: bool = False):
	"""
	Sorts tasks in topographical order, such that a task comes after any of its
	upstream dependencies.
	Heavily inspired by:
	http://blog.jupo.org/2012/04/06/topological-sorting-acyclic-directed-graphs/
	:param include_subdag_tasks: whether to include tasks in subdags, default to False
	:return: list of tasks in topological order
	"""

Narrator: it wasn't. It never is

[eladkal]

i wonder if using topological_sort may also solve #13044 ?

[ashb]

@eladkal Nope, that's purely an artefact of the chart/graphing libary we are using on the front end as expanding the collapsed TG doesn't request any new data -- it's already there in the nodes JS var