Allow read-passwd to hide characters inserted by C-y. (Security fix.)

Allow read-passwd to hide characters inserted by C-y.  (Security fix.)

This fixes bug #30186.  The with-silent-modifications was there to prevent
records of text property manipulations being put into buffer-undo-list.  These
had been causing a significant slowdown in CC Mode with C-_ after a large
C-y.  This CC Mode problem has since been solved by a different workaround.

* lisp/subr.el (remove-yank-excluded-properties): Remove the invocation of
with-silent-modifications around the text property manipulations.