Fix the A11y issues in the InternetTile

1. The WiFi enable state should always be updated even when qsIcon=null
2. The secondary label should be added into the description no matter
the WiFi is enabled or not as long as the secondary label is not empty.

Bug: 179499535
Test: Manual Tests
Change-Id: If9a2e622299e3073649fc44cc9b752f19432c800