Fix module icon for Alchemy 7.4

Alchemy 7.4 splitted the icon name from the style.
line is the default style, so we can just omit it
for all Alchemy version larger than equal to 7.4.0.a

Author: tvdeyen

config/initializers/alchemy.rb

@@ -3,6 +3,16 @@
 Rails.application.config.to_prepare do
   require "alchemy/devise/ability"
 
+  alchemy_7_4 = Gem::Version.new("7.4.0.a")
+
+  icon = if Alchemy.gem_version.between? Gem::Version.new("7.1.0-b1"), alchemy_7_4
+    "group-line"
+  elsif Alchemy.gem_version > alchemy_7_4
+    "group"
+  else
+    "users"
+  end
+
   Alchemy.register_ability(Alchemy::Devise::Ability)
 
   Alchemy::Modules.register_module({
@@ -13,7 +23,7 @@
       name: "modules.users",
       controller: "/alchemy/admin/users",
       action: "index",
-      icon: (Alchemy.gem_version > Gem::Version.new("7.1.0-b1")) ? "group-line" : "users"
+      icon: icon
     }
   })