fix warn

[ranocha]

I got an error

ERROR: UndefVarError: `warn` not defined
Stacktrace:
 [1] pause_main_loop(f::ProfileView.var"#7#8")
   @ Gtk4.GLib ~/.julia/packages/Gtk4/BHOnE/src/GLib/loop.jl:163
 [2] view(; kwargs::@Kwargs{windowname::String})
   @ ProfileView ~/.julia/packages/ProfileView/eDYNi/src/ProfileView.jl:210
 [3] macro expansion
   @ ~/.julia/packages/ProfileView/eDYNi/src/ProfileView.jl:125 [inlined]
 [4] top-level scope
   @ REPL[14]:1

This PR should fix it.

[jwahlstrand]

Thanks!