update docs and remove redundant import

docs/docs/installation/alerts-reports.mdx

@@ -371,7 +371,7 @@ to specify on behalf of which username to render the dashboards. In general dash
 are not accessible to unauthorized requests, that is why the worker needs to take over credentials
 of an existing user to take a snapshot.
 
-By default, Alerts and Reports are executed by the user that the `THUMBNAIL_SELENIUM_USER` config
+By default, Alerts and Reports are executed as the user that the `THUMBNAIL_SELENIUM_USER` config
 parameter is set to. To change this user, just change the config as follows:
 
 ```python
@@ -382,13 +382,23 @@ In addition, it's also possible to execute the reports as the report owners/crea
 needed if there isn't a central service account that has access to all objects or databases (e.g.
 when using user impersonation on database connections). For this there's the config flag
 `ALERTS_REPORTS_EXECUTE_AS` which makes it possible to customize how alerts and reports are executed.
-For example, to first try to execute as the creator, then fall back to last modifier if the creator is
-undefined, then an owner (it will first prioritize the last modifier and then the creator if either is
-contained within the list of owners, otherwise the first owner owner will be used) and finally
-`THUMBNAIL_SELENIUM_USER` if no creators, modifiers or owners are found, set as follows:
+To first try to execute as the creator in the owners list (if present), then fall
+back to the creator, then the last modifier in the owners list (if present), then the
+last modifier, then an owner (giving priority to the last modifier and then the
+creator if either is contained within the list of owners, otherwise the first owner
+will be used) and finally `THUMBNAIL_SELENIUM_USER`, set as follows:
 
 ```python
-ALERT_REPORTS_EXECUTE_AS = ["creator", "modifier", "owner", "selenium"]
+from superset.reports.types import ReportScheduleExecutor
+
+ALERT_REPORTS_EXECUTE_AS = [
+    ReportScheduleExecutor.CREATOR_OWNER,
+    ReportScheduleExecutor.CREATOR,
+    ReportScheduleExecutor.MODIFIER_OWNER,
+    ReportScheduleExecutor.MODIFIER,
+    ReportScheduleExecutor.OWNER,
+    ReportScheduleExecutor.SELENIUM,
+]
 ```
 
 **Important notes**

tests/integration_tests/reports/commands_tests.py

@@ -56,6 +56,7 @@
     ReportScheduleValidatorType,
     ReportState,
 )
+from superset.reports.types import ReportScheduleExecutor
 from superset.utils.database import get_example_database
 from tests.integration_tests.fixtures.birth_names_dashboard import (
     load_birth_names_dashboard_with_slices,
@@ -671,11 +672,11 @@ def test_email_chart_report_schedule_alpha_owner(
 ):
     """
     ExecuteReport Command: Test chart email report schedule with screenshot
-    executed as the chart creator
+    executed as the chart owner
     """
     config_key = "ALERT_REPORTS_EXECUTE_AS"
     original_config_value = app.config[config_key]
-    app.config[config_key] = ["owner"]
+    app.config[config_key] = [ReportScheduleExecutor.OWNER]
 
     # setup screenshot mock
     username = ""

tests/integration_tests/reports/utils.py

@@ -16,7 +16,7 @@
 # under the License.
 
 import json
-from contextlib import contextmanager, nullcontext
+from contextlib import contextmanager
 from typing import Any, Dict, List, Optional
 from uuid import uuid4