feat: add "e2ee encrypted" info message to all e2ee chats (#7008)

this PR adds a info message "messages are end-to-end-encrypted" also for
chats created by eg. vcards. by the removal of lock icons, this is a
good place to hint for that in addition; this is also what eg. whatsapp
and others are doing

the wording itself is tweaked at
https://github.com/deltachat/deltachat-android/pull/3817 (and there is
also the rough idea to make the message a little more outstanding, by
some more dedicated colors)

~~did not test in practise, if this leads to double "e2ee info messages"
on secure join, tests look good, however.~~ EDIT: did lots of practise
tests meanwhile :)

most of the changes in this PR are about test ...

ftr, in another PR, after 2.0 reeases, there could probably quite some
code cleanup wrt set-protection, protection-disabled etc.

---------

Co-authored-by: Hocuri <hocuri@gmx.de>

deltachat-rpc-client/tests/test_something.py

@@ -12,6 +12,7 @@ import pytest
 
 from deltachat_rpc_client import Contact, EventType, Message, events
 from deltachat_rpc_client.const import ChatType, DownloadState, MessageState
+from deltachat_rpc_client.pytestplugin import E2EE_INFO_MSGS
 from deltachat_rpc_client.rpc import JsonRpcError
 
 
@@ -457,8 +458,12 @@ def test_wait_next_messages(acfactory) -> None:
         alice_chat_bot.send_text("Hello!")
 
         next_messages = next_messages_task.result()
-        assert len(next_messages) == 1
-        snapshot = next_messages[0].get_snapshot()
+
+        if len(next_messages) == E2EE_INFO_MSGS:
+            next_messages += bot.wait_next_messages()
+
+        assert len(next_messages) == 1 + E2EE_INFO_MSGS
+        snapshot = next_messages[0 + E2EE_INFO_MSGS].get_snapshot()
         assert snapshot.text == "Hello!"