Only handle saveToStore from the WifiNetworkSuggestionsManager

Suggestion app may add a list of passpoint suggestions, only saveToStore
once to reduce the number of writing xml.
Also remove the suggestions which trigger the OOM exception

Bug: 245299920
Test: atest com.android.server.wifi
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:c11c594c05cc16379d66c324ec5261484cce87f8)
Merged-In: I8fd038c41399f9f04dda278a6e67b8a5d1d42e44
Change-Id: I8fd038c41399f9f04dda278a6e67b8a5d1d42e44
4 files changed