feat: Delete vg-request-with-auth from IMAP after processing (#6208)

In multi-device case `vg-request-with-auth` left on IMAP may result in situation when Bob joins the
group, then leaves it, then second Alice device comes online and processes `vg-request-with-auth`
again and adds Bob back. So we should IMAP-delete `vg-request-with-auth`. Another device will know
the Bob's key from Autocrypt-Gossip. But also we should make sure that `vg-member-added` is sent
before that. For this, add a new `imap.target_min_smtp_id` column and only move or delete emails
when `smtp.id` reaches the `imap.target_min_smtp_id` value.

deltachat-rpc-client/tests/test_securejoin.py

@@ -73,6 +73,9 @@ def test_qr_securejoin(acfactory, protect, tmp_path):
     qr_code = alice_chat.get_qr_code()
     bob.secure_join(qr_code)
 
+    # Alice deletes "vg-member-added", SecureJoin succeeds before that.
+    alice.wait_for_securejoin_inviter_success()
+
     # Check that at least some of the handshake messages are deleted.
     for ac in [alice, bob]:
         while True:
@@ -80,13 +83,12 @@ def test_qr_securejoin(acfactory, protect, tmp_path):
             if event["kind"] == "ImapMessageDeleted":
                 break
 
-    alice.wait_for_securejoin_inviter_success()
-
     # Test that Alice verified Bob's profile.
     alice_contact_bob = alice.get_contact_by_addr(bob.get_config("addr"))
     alice_contact_bob_snapshot = alice_contact_bob.get_snapshot()
     assert alice_contact_bob_snapshot.is_verified
 
+    # Bob deletes "vg-request-with-auth", SecureJoin succeeds later.
     bob.wait_for_securejoin_joiner_success()
 
     snapshot = bob.get_message_by_id(bob.wait_for_incoming_msg_event().msg_id).get_snapshot()