[SB Refactor] Un-ignore #onDarkChanged tests.

See reasoning in bug.

Fixes: 262660044
Test: `atest ModernStatusBarWifiViewTest#onDarkChanged_iconHasNewColor
--iterations 100` -> all pass

Change-Id: Ic38b9698afab43f274007d9f66ff73675f526a1e
2 files changed