bug#61553: 29.0.60; Inconsistent use of dialog boxes by read-multiple-choice

[Augusto Stoffel]

In the scratch buffer of emacs -Q, type

    (read-multiple-choice "Question" '((?y "yes") (?n "no")))

then click, on the menu bar, "Lisp-Interaction -> Evaluate and Print".
As expected, I see a dialog box.

Now repeat the same using the long-form style:

    (read-multiple-choice "Question" '((?y "yes") (?n "no")) nil nil t)

Then I get a minibuffer query, but I would expect a dialog box in the
case as well.

As a more concrete example, when clicking the "File -> Close" menu item
in a modified buffer, I would expect a to always get a dialog box for
the "buffer modified, kill anyway?" question.  (assuming of course
use-dialog-box is t).  Currently, one gets a minibuffer query by
default.  This change from mouse interaction to keyboard interaction
seems unexpected to me.