For few settings like `waiting_period_threshold` it makes sense to have the
"value" attribute of option to have a value other than the actual setting
value because multiple settings are depending upon this dropdown, so
handling them in JS code makes more sense. But for many settings (which has
integer values), we have followed a wrong trend over the time of
representing every new dropdown with human-readable values and manually
handling them in JS Code, where it makes more sense to use actual setting
value. The result of which is code has become less concise, sensible and
less likely to be mistaken.
This is a preliminary commit for upcoming change where we will use
"bot_creation_policy_values" like approach for many other settings where
dropdown represents the only single setting of integer type.
This experimental setting disables sending private messages in Zulip
in a crude way (i.e. users get an error when they try to send one).
It makes no effort to adjust the UI to avoid advertising the idea of
sending private messages.
Fixes#6617.