[Provider Model] Simplify filtering WiFi list function

- When the WiFi network status changes, if it takes too long to filter
the WiFi list, then the result might have a gap in the second filter.

- Avoid multiple filtering

- Remove unnecessary code

Bug: 207672135
Test: manual test
atest -c InternetDialogTest

Change-Id: I66f58a1e03847d54f052388fd6efa97eb7dc069e