Fix WifiConnectivityManagerTest test

The flaky is caused by SystemClock in the handler is not able to mock. Add delay and release the interval check.

Bug: 288342050
Bug: 321201969
Test: atest WifiConnectivityManagerTest
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:5efd2c22dfc9c280848d329ba7dbf5809c79aa9d)
Merged-In: I987b6b7c28bc675ff222789bd47d172698b59ac9
Change-Id: I987b6b7c28bc675ff222789bd47d172698b59ac9
2 files changed