chore(welcome): change default last tab to "all" (#22798)

UPDATING.md

@@ -34,6 +34,7 @@ assists people when migrating to a new version.
 
 ### Breaking Changes
 
+- [22798](https://github.com/apache/superset/pull/22798): To make the welcome page more relevant in production environments, the last tab on the welcome page has been changed from to feature all charts/dashboards the user has access to (previously only examples were shown). To keep current behavior unchanged, add the following to your `superset_config.py`: `WELCOME_PAGE_LAST_TAB = "examples"`
 - [22328](https://github.com/apache/superset/pull/22328): For deployments that have enabled the "THUMBNAILS" feature flag, the function that calculates dashboard digests has been updated to consider additional properties to more accurately identify changes in the dashboard metadata. This change will invalidate all currently cached dashboard thumbnails.
 - [21765](https://github.com/apache/superset/pull/21765): For deployments that have enabled the "ALERT_REPORTS" feature flag, Gamma users will no longer have read and write access to Alerts & Reports by default. To give Gamma users the ability to schedule reports from the Dashboard and Explore view like before, create an additional role with "can read on ReportSchedule" and "can write on ReportSchedule" permissions. To further give Gamma users access to the "Alerts & Reports" menu and CRUD view, add "menu access on Manage" and "menu access on Alerts & Report" permissions to the role.
 

superset/config.py

@@ -1498,16 +1498,16 @@ def EMAIL_HEADER_MUTATOR(  # pylint: disable=invalid-name,unused-argument
     "port": internet_port,
 }
 
-# By default, the Welcome page features example charts and dashboards. This can be
-# changed to show all charts/dashboards the user has access to, or a custom view
+# By default, the Welcome page features all charts and dashboards the user has access
+# to. This can be changed to show only examples, or a custom view
 # by providing the title and a FAB filter:
 # WELCOME_PAGE_LAST_TAB = (
 #     "Xyz",
 #     [{"col": 'created_by', "opr": 'rel_o_m', "value": 10}],
 # )
 WELCOME_PAGE_LAST_TAB: Union[
     Literal["examples", "all"], Tuple[str, List[Dict[str, Any]]]
-] = "examples"
+] = "all"
 
 # Configuration for environment tag shown on the navbar. Setting 'text' to '' will hide the tag.
 # 'color' can either be a hex color code, or a dot-indexed theme color (e.g. error.base)