Existing request prompt should be removed when custom prompt is used

[orenyk]

As of v3.4.3, when a reservation request is created the user is presented with an admin-customizable prompt. However, the default prompt still appears below this one, if defined. We should:

• Place the default prompt inside the well, and
• Remove the default text when a custom message has been defined.

[orenyk]

This still needs to be fixed on master, but will hopefully be in v3.4.4