Improvement of the filter and model selection sidebar on the admin changelist page for mobile screens.

[Antoliny]

On the current changelist page, the model selection sidebar is set to display: none on mobile screen sizes, so it is not visible. In contrast, the filter sidebar is displayed at the bottom of the changelist.

In the above image, it's fine because the table has only one row. However, if the table contains multiple rows, it may be difficult to access the filter.
This layout can cause inconvenience to users and is something that I believe needs improvement.

Also, I think it would be better if the model selection sidebar is available on mobile screens as well. Not providing certain features depending on the screen size can also cause inconvenience to users.

I think it would be good to add a button like the one above for the side panel, and have the side panel appear when that button is clicked.
However, I think further discussion is needed regarding the exact design.