fix(dracula.sh): fix execution errors

Resolves an issue cause by a syntax error and a removed executable bit
introduced by dracula/tmux#153.

The syntax/permissions issue stops the plugin from running properly when
I ran into the issue earlier today.

The missing executable bit is likely what's causing dracula/tmux#178
given that `man bash` has the following excerpt:

> If a command is found but is not executable, the return status is 126.

scripts/dracula.sh

@@ -172,6 +172,7 @@ main()
     if [ $plugin = "spotify-tui" ]; then
       IFS=' ' read -r -a colors <<<$(get_tmux_option "@dracula-spotify-tui-colors" "green dark_gray")
       script="#($current_dir/spotify-tui.sh)"
+    fi
 
     if [ $plugin = "kubernetes-context" ]; then
       IFS=' ' read -r -a colors <<<$(get_tmux_option "@dracula-kubernetes-context-colors" "cyan dark_gray")