Whitelist settings robotests to access wifi impl details

The test is already accessing these via robolectric leaking the impl
jar, so make the dep explicit.

Note that the merged-in tag is unrelated to the actual change.

Bug: 157451444
Bug: 161767237
Test: m RunSettingsRoboTests
Merged-In: Ic1a14c34334eb276724d97c4e763360d51cb035b
Change-Id: Id283ecb2b9b8bd087028f9a68604adc516e9ea9e