core: do not show chat relay test connections in chat list

The connection created by APITestChatRelay has conn_type = contact and no
chat entity, so the only thing keeping it out of the chat list was the
filter on prepared status - and the agent event handler moves it past that
status (CONF sets it to requested) before the relay test result arrives.
So a relay test shows a phantom "connecting" chat while it runs, and
permanently if the app is killed before the test deletes the connection.

src/Simplex/Chat/Store/Messages.hs

@@ -1194,6 +1194,7 @@ getContactConnectionChatPreviews_ db User {userId} pagination clq = case clq of
         WHERE user_id = ?
           AND conn_type = ?
           AND conn_status != ?
+          AND relay_test = 0
           AND contact_id IS NULL
           AND conn_level = 0
           AND via_contact IS NULL

src/Simplex/Chat/Store/SQLite/Migrations/chat_query_plans.txt

@@ -2038,6 +2038,7 @@ Query:
         WHERE user_id = ?
           AND conn_type = ?
           AND conn_status != ?
+          AND relay_test = 0
           AND contact_id IS NULL
           AND conn_level = 0
           AND via_contact IS NULL
@@ -2055,6 +2056,7 @@ Query:
         WHERE user_id = ?
           AND conn_type = ?
           AND conn_status != ?
+          AND relay_test = 0
           AND contact_id IS NULL
           AND conn_level = 0
           AND via_contact IS NULL
@@ -2072,6 +2074,7 @@ Query:
         WHERE user_id = ?
           AND conn_type = ?
           AND conn_status != ?
+          AND relay_test = 0
           AND contact_id IS NULL
           AND conn_level = 0
           AND via_contact IS NULL