rm qt icons file

so we don't need pyrcc5, which is not deterministic,
and so we don't need the submodule for the icons

based on electrumsv/electrumsv@bf8802c2ea

contrib/deterministic-build/check_submodules.sh

@@ -18,13 +18,6 @@ function get_git_mtime {
 
 fail=0
 
-for f in icons/* "icons.qrc"; do
-    if (( $(get_git_mtime "$f") > $(get_git_mtime "contrib/deterministic-build/electrum-icons/") )); then
-        echo "Modification time of $f (" $(get_git_mtime --readable "$f") ") is newer than"\
-             "last update of electrum-icons"
-        fail=1
-    fi
-done
 
 if [ $(date +%s -d "2 weeks ago") -gt $(get_git_mtime "contrib/deterministic-build/electrum-locale/") ]; then
     echo "Last update from electrum-locale is older than 2 weeks."\