Add default small sleep time

[hiberabyss]

When ssh via script, the pane_current_command could not recognize the ssh command. Add default sleep to make <C-a> posssible.

[bruno-]

I worry that the downside of this approach is that it adds delay for all invocations of this script. Also 0.05 may not be enough for ssh connections with higher latency. Our current wait time for ssh is 0.4s.

A solution that may work would be to add a config option to recognize other programs on this line
https://github.com/tmux-plugins/tmux-yank/pull/149/files#diff-c32e2a4d1e5d659439fb939a2f802471a715a95e7a9f98d87a257f7ca847af2bR22