Remove use of forceUpdate.

Now that WifiTracker correctly handles eviction of stale scan results
only after scanning has resumed, it is no longer necessary to
conditionally fetch APs on app resumption.

Fix broken test.

Bug: 68030053
Test: runtest --path
tests/unit/src/com/android/settings/wifi/WifiSettingsUiTest.java

Change-Id: Ib4c8d6e53cf760fcb5f00069da40c578171c09f4