fix: Free XMPPStanza objects in verify_any and verify_last

The XMPPStanza objects created by stanza_parse() in verify_any() and
verify_last() functions were never freed, causing memory leaks.

This fix adds stanza_free(stanza) calls before the return statements
to properly release the allocated stanza resources.

src/server/verify.c

@@ -72,6 +72,7 @@ verify_any(char *stanza_text, gboolean ign_timeout)
         log_println(STBBR_LOGINFO, "VERIFY FAIL: %s", stanza_text);
     }
 
+    stanza_free(stanza);
     return result;
 }
 
@@ -106,5 +107,6 @@ verify_last(char *stanza_text)
         stanzas_debug_last();
     }
 
+    stanza_free(stanza);
     return result;
 }