Fix update of ZenModeFragment while in started (but not resumed) state

We were skipping it to avoid a double-update on first fragment launch (create->start->resume) because DashboardFragment automatically updates onResume. However, this meant that no updates actually got through in the started state.

Instead, avoid the double-update by ignoring first start only.

Fixes: 417616471
Test: atest ZenModeFragmentBaseTest + manual
Flag: EXEMPT Trivial bugfix
Change-Id: I6ba0d7454f284fb9705466ceb81ade5d57cfdbc5