Bump version code and legacy group deprecated dates for internal test release

app/build.gradle

@@ -15,7 +15,7 @@ configurations.configureEach {
     exclude module: "commons-logging"
 }
 
-def canonicalVersionCode = 391
+def canonicalVersionCode = 393
 def canonicalVersionName = "1.21.0"
 
 def postFixSize = 10

libsession/src/main/java/org/session/libsession/messaging/groups/LegacyGroupDeprecationManager.kt

@@ -33,7 +33,7 @@ class LegacyGroupDeprecationManager(private val prefs: TextSecurePreferences)  {
     val deprecatedTime: StateFlow<ZonedDateTime> get() = mutableDeprecatedTime
 
     // The time a warning will be shown to users that legacy groups are being deprecated.
-    private val defaultDeprecatingStartTime = ZonedDateTime.of(2025, 6, 23, 0, 0, 0, 0, ZoneId.of("UTC"))
+    private val defaultDeprecatingStartTime = ZonedDateTime.of(2025, 2, 24, 0, 0, 0, 0, ZoneId.of("UTC"))
 
     private val mutableDeprecatingStartTime: MutableStateFlow<ZonedDateTime> = MutableStateFlow(
         prefs.deprecatingStartTimeOverride ?: defaultDeprecatingStartTime