Have 'delete-frame' delete initial daemon frame only if FORCE is non-nil

Have 'delete-frame' delete initial daemon frame only if FORCE is non-nil

* src/frame.c (delete_frame): Delete initial daemon frame only
if FORCE is non-nil (Bug#78583).
(Fdelete_frame): Rewrite doc-string to mention that it can
delete an initial daemon frame if and only if FORCE is non-nil.
* etc/NEWS:
* doc/lispref/frames.texi (Deleting Frames): Mention that
'delete-frame' can delete an initial daemon frame if and only if
FORCE is non-nil.

(cherry picked from commit 433a031d249a28a29bdc6c2c4cf880f26a262627)