fix(copybuffer): define CTRL+O binding for all keymaps (#6442)

Fixes #6442

plugins/copybuffer/copybuffer.plugin.zsh

@@ -11,4 +11,6 @@ copybuffer () {
 
 zle -N copybuffer
 
-bindkey "^O" copybuffer
+bindkey -M emacs "^O" copybuffer
+bindkey -M viins "^O" copybuffer
+bindkey -M vicmd "^O" copybuffer