bug#53561: Failing: guix package -i gtkmm@3

[Dale Mellor]

The above command produces

The following package will be installed:
   gtkmm 3.24.5

guix package: error: profile contains conflicting entries for libsigc++
guix package: error:   first entry: libsigc++@3.0.6 
/gnu/store/ng4k2yl94d758p5vnashd4nvyb1aw8s1-libsigc++-3.0.6
guix package: error:    ... propagated from cairomm@1.14.2
guix package: error:    ... propagated from gtkmm@3.24.5
guix package: error:   second entry: libsigc++@2.9.3 
/gnu/store/iad8jg1fm7jsq0pqj547f3n5s2jn9rp0-libsigc++-2.9.3
guix package: error:    ... propagated from glibmm@2.64.5
guix package: error:    ... propagated from pangomm@2.46.0
guix package: error:    ... propagated from gtkmm@3.24.5
hint: You cannot have two different versions or variants of `gtkmm' in the same 
profile.