fix(ui): avoid recursiveness and invalid memory access #28578

Problem:  Calling :redraw from vim.ui_attach() callback results in
          recursive cmdline/message events.
Solution: Avoid recursiveness where possible and replace global "call_buf"
          with separate, temporary buffers for each event so that when a Lua
          callback for one event fires another event, that does not result
          in invalid memory access.

src/nvim/ui.h

@@ -14,6 +14,7 @@
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # include "ui.h.generated.h"
 # include "ui_events_call.h.generated.h"
+EXTERN Array noargs INIT(= ARRAY_DICT_INIT);
 #endif
 // uncrustify:on