Remove en-GB option since we don't actually localize different English locales

(cherry picked from commit 0cb042cd93)

# Conflicts:
#	app/build.gradle.kts

app/src/main/java/exh/EXHMigrations.kt

@@ -329,6 +329,10 @@ object EXHMigrations {
                 if (oldVersion under 21) {
                     // Setup EH updater task after migrating to WorkManager
                     EHentaiUpdateWorker.scheduleBackground(context)
+
+                    if (preferences.lang().get() in listOf("en-US", "en-GB")) {
+                        preferences.lang().set("en")
+                    }
                 }
 
                 // if (oldVersion under 1) { } (1 is current release version)