fix: add missing omemo_is_jid_trusted(), auto_gerror macro, and titlebar variable declarations

Fixes build errors from cherry-picked upstream patches:
- Add omemo_is_jid_trusted() function (from upstream trust indicator feature)
- Add auto_gerror/PROF_GERROR_MESSAGE macros (needed by /changes command)
- Add trusted_attrs/untrusted_attrs declarations in _show_muc_privacy()
- Remove stale 'error' reference in omemo_receive_message()

tests/unittests/omemo/stub_omemo.c

@@ -42,6 +42,12 @@ omemo_is_trusted_identity(const char* const jid, const char* const fingerprint)
     return TRUE;
 }
 
+gboolean
+omemo_is_jid_trusted(const char* const jid)
+{
+    return TRUE;
+}
+
 GList*
 omemo_known_device_identities(const char* const jid)
 {