Creating a Template Part and not assigning a name creates an error

[jameskoster]

When you create a template part via the ellipsis menu in the block toolbar, the following occurs:

tp.name.mp4

[talldan]

I just tested this and noticed the error no longer happens. Instead an Untitled Template Part is created:

From working on the navigation block, the feedback there was that calling things 'untitled' isn't desirable. It might be that there's still some work to do here.

[jameskoster]

Yeah we should probably make the name a required field.

[talldan]

Fixed by #36592