Trace pixel art - missing warning

Summary:

in 0.924 we have pop up warning if you try to trace a pixel are wich is bigger than ~400px

Steps to reproduce:

• open Inkscape
• import image bigger than 400px
• go to path/trace bitmap
• switch to the pixel art tab
• trace

What happened?

• it starts tracing (and probably freeze forever)

What should have happened?

• should issue a warning that this step will probably result in freeze with big pictures and ask you to save frist

Sample attachments:

Version Info:

Inkscape 1.1-rc (52f87abb, 2021-05-02)

GLib version:     2.68.1
GTK version:      3.24.29
glibmm version:   2.66.0
gtkmm version:    3.24.3
libxml2 version:  2.9.10
libxslt version:  1.1.34
Cairo version:    1.17.4
Pango version:    1.48.4
HarfBuzz version: 2.8.0
Poppler version:  20.12.1

OS version:       Windows 10 2009