Register external tool attributes for Ada too

This is needed in order to recognize and read project attributes
via the 'als-get-project-attribute-value' command, which is
used by the VS Code extension.'

For eng/ide/ada_language_server#1375

Author: AnthonyLeonardoGracio

source/ada/lsp-ada_driver.adb

@@ -599,9 +599,9 @@ begin
    Server.Initialize (Stream'Unchecked_Access);
 
    begin
-      if VSS.Command_Line.Is_Specified (Language_GPR_Option) then
+      LSP.GPR_External_Tools.Initialize_Extra_Packages_Attributes;
 
-         LSP.GPR_External_Tools.Initialize_Extra_Packages_Attributes;
+      if VSS.Command_Line.Is_Specified (Language_GPR_Option) then
 
          Server.Register_Handler
            (LSP.Server_Notifications.DidChange.Notification'Tag,