5f6c55a724
In order to solve the "double notification" issue (see:
ef5e5fa03f)
without running the plugin process under a new pgid (see:
https://github.com/moby/moby/issues/47073) we instead check if we're
attached to a TTY, and if so skip signalling the plugin process since it
will already be signalled.
Signed-off-by: Laura Brehm <laurabrehm@hey.com>