The link is not displayed when str is blank in admin.

[Antoliny]

In the admin page, there are parts where the model's __str__ value is used, providing links that allow navigation to the object when the value is clicked.
However, when __str__ is blank, while it’s not an issue for the value to appear as blank, the <a> tag's innerHTML being empty prevents the layout from being displayed on the screen, and it also cannot function as a link.

While it’s very rare for a user to assign a blank value to __str__, I still believe that it should at least function as a link.
Just like with fields, when the value is blank, a default value such as "-" should be used to ensure that it can at least function as a link.

[Sarah Boyce]

Similar nature to #36114
It will be difficult to find all of these but we can try 👍

[Antoliny]

I have confirmed that this issue also occurs in the breadcrumb. Additionally, while a message can still function as a link even when it is blank, it may need to be changed for consistency, so I have added that.

[Antoliny]

​PR