make chat names always searchable (#3377)

* test contact name changes applied everywhere

this test is failing on current master,
a changed authname is set to `contact.authname` but not cached at `chat.name`;
resulting in `dc_chat_get_name()` returning a name
undiscoverable by `dc_get_chatlist(name)`.

* fix: update chat.name on contact.authname changes

* do read contact.display_name from database only of chat.name is empty

* update CHANGELOG

CHANGELOG.md

@@ -4,7 +4,10 @@
 
 ### Changes
 - refactorings #3373 #3345
+
+### Fixes
 - delete outgoing MDNs found in the Sent folder on Gmail #3372
+- fix searching one-to-one chats #3377
 
 
 ## 1.84.0