Display execution_date in graph view task instance tooltip. (#32527)

* Fix displaying execution_date in graph view task instance tooltip.

* Fix tests.
diff --git a/airflow/www/utils.py b/airflow/www/utils.py
index bcf368e..8d5ee60 100644
--- a/airflow/www/utils.py
+++ b/airflow/www/utils.py
@@ -84,7 +84,10 @@
 
 def get_instance_with_map(task_instance, session):
     if task_instance.map_index == -1:
-        return alchemy_to_dict(task_instance)
+        data = alchemy_to_dict(task_instance)
+        # Fetch execution_date explicitly since it's not a column and a proxy
+        data["execution_date"] = task_instance.execution_date
+        return data
     mapped_instances = get_mapped_instances(task_instance, session)
     return get_mapped_summary(task_instance, mapped_instances)
 
@@ -137,6 +140,7 @@
         "end_date": group_end_date,
         "mapped_states": mapped_states,
         "try_number": get_try_count(parent_instance._try_number, parent_instance.state),
+        "execution_date": parent_instance.execution_date,
     }
 
 
diff --git a/tests/www/views/test_views_tasks.py b/tests/www/views/test_views_tasks.py
index d8c6a48..32df99c 100644
--- a/tests/www/views/test_views_tasks.py
+++ b/tests/www/views/test_views_tasks.py
@@ -1013,6 +1013,7 @@
             "dag_id": "example_bash_operator",
             "duration": None,
             "end_date": None,
+            "execution_date": DEFAULT_DATE.isoformat(),
             "executor_config": {},
             "external_executor_id": None,
             "hostname": "",
@@ -1044,6 +1045,7 @@
             "dag_id": "example_bash_operator",
             "duration": None,
             "end_date": None,
+            "execution_date": DEFAULT_DATE.isoformat(),
             "executor_config": {},
             "external_executor_id": None,
             "hostname": "",
@@ -1075,6 +1077,7 @@
             "dag_id": "example_bash_operator",
             "duration": None,
             "end_date": None,
+            "execution_date": DEFAULT_DATE.isoformat(),
             "executor_config": {},
             "external_executor_id": None,
             "hostname": "",
@@ -1106,6 +1109,7 @@
             "dag_id": "example_bash_operator",
             "duration": None,
             "end_date": None,
+            "execution_date": DEFAULT_DATE.isoformat(),
             "executor_config": {},
             "external_executor_id": None,
             "hostname": "",
@@ -1137,6 +1141,7 @@
             "dag_id": "example_bash_operator",
             "duration": None,
             "end_date": None,
+            "execution_date": DEFAULT_DATE.isoformat(),
             "executor_config": {},
             "external_executor_id": None,
             "hostname": "",
@@ -1168,6 +1173,7 @@
             "dag_id": "example_bash_operator",
             "duration": None,
             "end_date": None,
+            "execution_date": DEFAULT_DATE.isoformat(),
             "executor_config": {},
             "external_executor_id": None,
             "hostname": "",
@@ -1199,6 +1205,7 @@
             "dag_id": "example_bash_operator",
             "duration": None,
             "end_date": None,
+            "execution_date": DEFAULT_DATE.isoformat(),
             "executor_config": {},
             "external_executor_id": None,
             "hostname": "",