bug#30938: 27.0; `dired-do-create-files' etc.: do NOT always raise error if no files

[Juri Linkov]

> I'm open to other ways to do what is needed, if they
> are better.  Feel free to propose something.

I still don't see why raising the error should depend on command's
interactivity, i.e. why these commands should not signal a user-error
in the non-interactive case.

We have thousands calls of such core functions as
(search-forward STRING &optional BOUND NOERROR COUNT)
and none of them binds the NOERROR arg to the command INTERACTIVE arg.
That's because it would make the control flow unmanageable in
a chain of commands, i.e. when a command that invokes a command
that invokes such core functions.

In very rare cases when you absolutely need to ignore errors,
just use (ignore-errors (dired-do-chmod))