Rename Non-protected variables

[brodrigu]

In Reporting in Sparrow, you define non-protected variables:

Non-protected variables
Many variables are relevant for one player only, like ad labels (click, view, click id), ABTest ID (see ABTest section below), and the interest group for the advertiser. These variables should be hidden to the other players and do not need other specific attention in this report, they do not represent any risk with regard to the user privacy and can be reported as is per display.

Non-protected suggests these variables are available to anyone.

I would suggest using private to align with class variable types or perhaps hidden or single-party to more accurately describe how they are treated.