Skip import of existing accounts

app/src/main/java/eu/faircode/email/ActivitySetup.java

@@ -879,6 +879,10 @@ public class ActivitySetup extends ActivityBase implements FragmentManager.OnBac
                             JSONObject jaccount = (JSONObject) jaccounts.get(a);
                             EntityAccount account = EntityAccount.fromJSON(jaccount);
 
+                            EntityAccount existing = db.account().getAccountByUUID(account.uuid);
+                            if (existing != null)
+                                continue;
+
                             if (account.auth_type == AUTH_TYPE_GMAIL) {
                                 if (GmailState.getAccount(context, account.user) == null) {
                                     Log.i("Google account not found user=" + account.user);

app/src/main/java/eu/faircode/email/DaoAccount.java

@@ -90,6 +90,9 @@ public interface DaoAccount {
     @Query("SELECT * FROM account WHERE id = :id")
     EntityAccount getAccount(long id);
 
+    @Query("SELECT * FROM account WHERE uuid = :uuid")
+    EntityAccount getAccountByUUID(String uuid);
+
     @Query("SELECT * FROM account WHERE name = :name")
     EntityAccount getAccount(String name);