[SettingsProvider] mem limit should be checked before settings are updated

Previously, a setting is updated before the memory usage limit
check, which can be exploited by malicious apps and cause OoM DoS.

This CL changes the logic to checkMemLimit -> update -> updateMemUsage.

BUG: 239415861
Test: atest com.android.providers.settings.SettingsStateTest

(cherry picked from commit 8eeb9295)
Merged-In: I20551a2dba9aa79efa0c064824f349f551c2c2e4
Change-Id: I20551a2dba9aa79efa0c064824f349f551c2c2e4