Do not overwrite carrier/user edits with UNEDITED

The EDITED field stores the edit history of the APN, so if an APN
conflicts with an existing APN then when merging we should preserve the
EDITED field of the existing APN when the new APN is set to UNEDITED.

Bug: 68841424
Test: CarrierSettingsUpdater/.../ApnUpdaterTest.java
Change-Id: I25757c31f9b3a2f2cece0aaae95451a0e33d0903
Merged-In: I25757c31f9b3a2f2cece0aaae95451a0e33d0903
(cherry picked from commit 58cbcd9400cdc0006fc5f595ac7326caa6db43dd)
1 file changed