Use ET timezone for vpn cohort (#3930)

Task/Issue URL: https://app.asana.com/0/488551667048375/1206034019967211/f

### Description
Use ET tz for vpn cohort

### Steps to test this PR

_Test_
- [x] fresh install from this branch
- [x] enable NetP
- [x] verify cohort is set in ET timezone

network-protection/network-protection-impl/src/main/java/com/duckduckgo/networkprotection/impl/cohort/NetPCohortUpdater.kt

@@ -27,6 +27,7 @@ import javax.inject.Inject
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.launch
 import org.threeten.bp.LocalDate
+import org.threeten.bp.ZoneId
 
 @ContributesMultibinding(
     scope = VpnScope::class,
@@ -50,7 +51,7 @@ class NetPCohortUpdater @Inject constructor(
         fun attemptToSetNetPCohort() {
             // skip if already stored
             cohortStore.cohortLocalDate?.let { return }
-            cohortStore.cohortLocalDate = LocalDate.now()
+            cohortStore.cohortLocalDate = LocalDate.now(ZoneId.of("America/New_York")) // ET time
         }
 
         coroutineScope.launch(dispatcherProvider.io()) {