Wipe the data in IpMemoryStore database upon network factory reset.

Bug:128499160
Test: manual
Test: atest FrameworksNetTests NetworkStackTests
Merged-In: I13ad04454e638905b74dd42a1c83266c7c37652f
Merged-In: Ia13ff10a57c2043f6676976f23ecfb2d2a9a6ef0
(cherry picked from commit ef6ef68c48b869aa9960edd81c73f3d31391ae26)

Change-Id: I42507451d55a620c0e2d271c895ad158f348c1a5

• packages/NetworkStack/src/com/android/server/connectivity/ipmemorystore/IpMemoryStoreDatabase.java[diff]
• packages/NetworkStack/src/com/android/server/connectivity/ipmemorystore/IpMemoryStoreService.java[diff]
• packages/NetworkStack/tests/unit/src/com/android/server/connectivity/ipmemorystore/IpMemoryStoreServiceTest.java[diff]
• services/core/java/com/android/server/ConnectivityService.java[diff]
• services/net/java/android/net/IpMemoryStoreClient.java[diff]
• tests/net/java/android/net/IpMemoryStoreTest.java[diff]