refactor(sql): add query_map_vec()

This also replaces some cases where flatten()
was used, effectively ignoring the errors.

src/contact.rs

@@ -1282,14 +1282,10 @@ impl Contact {
 
         let list = context
             .sql
-            .query_map(
+            .query_map_vec(
                 "SELECT id FROM contacts WHERE id>? AND blocked!=0 ORDER BY last_seen DESC, id DESC;",
                 (ContactId::LAST_SPECIAL,),
                 |row| row.get::<_, ContactId>(0),
-                |ids| {
-                    ids.collect::<std::result::Result<Vec<_>, _>>()
-                        .map_err(Into::into)
-                },
             )
             .await?;
         Ok(list)