Fix WiFi activity icon displacements in statusbar

If there isn't any traffic, make icons visibility INVISIBLE
instead of GONE to avoid jumpy icons.

Issue: FP3-A11#246
Change-Id: Ia160436cf4d658bc868cb13d6f82f8fc07afa53b
(cherry picked from commit 3afef07e8564285cba38408ce9aaeb8350d5e6d2)
1 file changed