When exiting while using both -c and --exit-no-conn, the -s signal is not passed to the command.

[saltbo]

Describe the bug
When exiting while using both -c and --exit-no-conn, the -s signal is not passed to the command.

To Reproduce
terminal 1: nc -lk 4000

terminal2: ttyd -qW -s SIGINT asciinema rec -y -c bash

open browser: http://localhost:7681/

close the webpage after 3s

Expected behavior
receive the upload request in the terminal 1.

Screenshots
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Environment:

• OS: [e.g. macOS 10.15.2]
• Browser: [e.g. Chrome 79.0.3945.130]

Additional context
Add any other context about the problem here.