API graphs: Remove restriction on top-level constants

ql/src/codeql_ruby/ApiGraphs.qll

@@ -270,8 +270,7 @@ module API {
         or
         name = read.getName() and
         not exists(resolveScopeExpr(read)) and
-        not exists(read.getScopeExpr()) and
-        not exists(read.getValue())
+        not exists(read.getScopeExpr())
       )
       or
       exists(DataFlow::LocalSourceNode src, DataFlow::LocalSourceNode pred |

ql/test/library-tests/dataflow/api-graphs/test1.rb

@@ -13,7 +13,7 @@ Unknown.new.run #$ use=getMember("Unknown").instance.getReturn("run")
 Foo::Bar::Baz #$ use=getMember("Foo").getMember("Bar").getMember("Baz")
 
 Const = [1, 2, 3]
-Const.each do |c|
+Const.each do |c| #$ use=getMember("Const").getReturn("each")
     puts c
 end