Allow whitespace-only macro names

strtrim collapsed a name like " " to "" and the empty guard then
rejected the save, but a whitespace-only name is valid in vanilla and a
common way to make a name-less macro. Save the raw text and only reject
a truly empty box.

modules/macroicons.lua

@@ -72,7 +72,7 @@ pfUI:RegisterModule("macroicons", function ()
     end
 
     local function SaveMacroPopup()
-      local text = strtrim(picker.editbox:GetText())
+      local text = picker.editbox:GetText()
       if text == "" then return end
 
       local icon = iconPicker.GetIcon()