Disable wtf dropbox entries by default.

Create a list of dropbox tags that are disabled by default. Currently
all tags were enabled by default, so this allows the other way too. We
can then easily turn wtf event collection back on for dogfood.

Bug: 270132337
Test: N/A
Change-Id: Ia678215c34df6ba9a354b3011a90f8f445c493b2