BuildLinuxImage.sh: Remove forced light theme

src/platform/unix/BuildLinuxImage.sh.in

@@ -43,8 +43,6 @@ export LD_LIBRARY_PATH="\$DIR/bin"
 # 1) BambuStudio will segfault on systems where locale info is not as expected (i.e. Holo-ISO arch-based distro)
 # 2) BambuStudio will segfault with a boost logging error if ~/.config/BambuStudio doesn't exist on first run
 export LC_ALL=C
-# FIXME: BambuStudio doesn't respect dark mode; use GTK_THEME workaround from sigxcpu76                                      │
-export GTK_THEME=Adwaita:light
 mkdir -p \${HOME}/.config/BambuStudio/ 2> /dev/null
 
 exec "\$DIR/bin/@SLIC3R_APP_CMD@" "\$@"