Escape command sent to TmuxInterruptAndRun

[bobwhitelock]

And possibly other Vim Tmux commands.

E.g. running :CrRunCommand python3 -m pip install -e '.[test]' && pytest and then <CR> currently gives an error:

Error detected while processing function TmuxInterruptAndRun:
line    5:
E121: Undefined variable: test
E116: Invalid arguments for function Send_to_Tmux
Press ENTER or type command to continue

[bobwhitelock]

vim-test with tslime possibly already handles this correctly, using the above in a custom test command seems to work fine (so while this is an issue it's not a big deal in this case).