Handle 'eshell-pipe-broken' when evaluating Lisp forms in Eshell

Handle 'eshell-pipe-broken' when evaluating Lisp forms in Eshell

* lisp/eshell/esh-cmd.el (eshell-exec-lisp): Handle
'eshell-pipe-broken'.

* lisp/eshell/esh-io.el (eshell-output-object-to-target): Only signal
'eshell-pipe-broken' if the process being written to has finished.

* test/lisp/eshell/esh-proc-tests.el
(esh-proc-test/pipeline-connection-type/middle)
(esh-proc-test/pipeline-connection-type/last): Remove ':unstable'.

Ref: https://lists.gnu.org/archive/html/emacs-devel/2022-08/msg00524.html