Reactivate Selection mode on Wayland

[Photon89]

So far this crashes on X11 for some reason... It gives

[...]
INFO: gathering system information...

Shutter 0.99.4 Rev.1608
Linux photon-virtualbox 6.1.44-1-MANJARO #1 SMP PREEMPT_DYNAMIC Wed Aug  9 09:02:26 UTC 2023 x86_64 GNU/Linux

Manjaro Linux \r  (\n) (\l)



Glib 1.3293 
Gtk3 0.038 

Glib built for 2.76.4, running with 2.76.4

Can't call method "set_sensitive" on an undefined value at ./shutter line 4239.
        Shutter::App::fct_control_signals("block") called at ./shutter line 804
        Shutter::App::STARTUP(Shutter::App=HASH(0x5575fedce8d8)) called at /usr/lib/perl5/5.38/vendor_perl/Glib/Object/Introspection.pm line 67
        Glib::Object::Introspection::__ANON__(Shutter::App=HASH(0x5575fedce8d8)) called at ./shutter line 10981
zsh: segmentation fault (core dumped)  ./shutter