Update Merge Media copy to reflect previous copy change from "Hidden" to "Minimized" media

[noah-schechter]

The current Merge Media modal's description reads:

Merge media associated with this incident into another incident. Note that media that has been hidden from view (i.e., marked as hidden or removed) will not be merged.

Let's change it to:

Merge media associated with this incident into another incident. Note that media that has been hidden from view (i.e., marked as minimized or removed) will not be merged.

This is a one-word change from "hidden" to "minimized" to reflect our new language for hiding source material.