Remove activity and new-output indicators in iTerm and zsh

Question

I'm occasionally updating my iTerm prompt with zsh to update current time:

# in ~/.zshrc

PROMPT='[%D{%H:%M}]'$PROMPT

TMOUT=10

TRAPALRM() {
    zle reset-prompt
}

Since I have indicator-related options in iTerm enabled ("Show activity indicator" and "Show new-otput indicator" in Preferences > Appearance > Tabs), this occasional update, of course, results in tab showing spinning wheel for a brief time and a blue circle after that.

Is it possible to somehow disable both indicators only for this particular function (TRAPALRM) or for PROMPT updates in general?