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**Apache Airflow version**: 2.0.0


**Kubernetes version (if you are using kubernetes)** (use `kubectl version`): n/a


**What happened**:

When I click on the "Triggered DAG" Operator Link in TriggerDagRunOperator, I am redirected with a relative link.

![Screen Shot 2021-03-08 at 4 28 16 PM](https://user-images.githubusercontent.com/5952735/110399833-61f00100-802b-11eb-9399-146bfcf8627c.png)

The redirect uses the HTML base URL and not the airflow base URL. This is only an issue if the URLs do not match.

**What you expected to happen**:

I expect the link to take me to the Triggered DAG tree view (default view) instead of the base url of the service hosting the webserver. 

**How to reproduce it**:

Create an airflow deployment where the HTML base url doesn't match the airflow URL. 




tests/utils/test_helpers.py
#
#
#
import unittest
from datetime import datetime
import pytest
from airflow.models import TaskInstance
from airflow.models.dag import DAG
from airflow.operators.dummy import DummyOperator
from airflow.utils import helpers
from airflow.utils.helpers import build_airflow_url_with_query, merge_dicts
from tests.test_utils.config import conf_vars
class TestHelpers(unittest.TestCase):
    def test_render_log_filename(self):
        try_number = 1
        dag_id = 'test_render_log_filename_dag'
        task_id = 'test_render_log_filename_task'
        execution_date = datetime(2016, 1, 1)
        dag = DAG(dag_id, start_date=execution_date)
        task = DummyOperator(task_id=task_id, dag=dag)
        ti = TaskInstance(task=task, execution_date=execution_date)
        filename_template = "{{ ti.dag_id }}/{{ ti.task_id }}/{{ ts }}/{{ try_number }}.log"
        ts = ti.get_template_context()['ts']
        expected_filename = f"{dag_id}/{task_id}/{ts}/{try_number}.log"
        rendered_filename = helpers.render_log_filename(ti, try_number, filename_template)
        assert rendered_filename == expected_filename
    def test_chunks(self):