Check daemon is initialized before suppressing its init errors

Check daemon is initialized before suppressing its init errors

Previously, the default error handler would correctly suppress
unhandled errors raised when IS_DAEMON and the initial frame
was current, since this is the normal state of operation for a
daemon-mode Emacs.  However, this also incorrectly suppressed
errors raised while a daemon-mode Emacs was starting up.

Now, errors raised while a daemon-mode Emacs is starting up will be
handled just like errors when a non-daemon Emacs is starting up.

This was previously the case before changes for bug#1310 and
bug#1836, which added the suppression of errors when IS_DAEMON.
DAEMON_RUNNING didn't exist at the time of those changes, but now
it does, so we can do better.

* src/keyboard.c (Fcommand_error_default_function): Check
!DAEMON_RUNNING in addition to IS_DAEMON.  (Bug#68799)
* src/lisp.h (DAEMON_RUNNING): Add a clarifying comment about
what this #define means.