Fix Wi-Fi list adds same AP repeatedly

When switch AP security mode, several same APs are shown.

To fix this issue, append security type to preference
key for avoiding different APs have same key.
git fetch

Cherrypick of:
https://partner-android-review.googlesource.com/#/c/799829/

Bug: 37558394
Test: runtest --path
packages/apps/Settings/tests/unit/src/com/android/settings/wifi/WifiSettingsUiTest.java

Change-Id: I39621636f14b29e45ba96ff76dc3c21a4996a136