[SB][Tech Debt] Refactor MobileIconsInteractorTest to better flow APIs.

Removes all the jobs and replaces them with collectLastValue.

Bug: NONE
Test: atest MobileIconsInteractorTest
Flag: NONE (unit test refactor)
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:bd2112e75414261d3a472097dcbf66a74ae99255)
Merged-In: Ibb0ef3ce58fabde3d5e2bf2b709e1cfc3a9198e7
Change-Id: Ibb0ef3ce58fabde3d5e2bf2b709e1cfc3a9198e7