fix GPIO0 mode after I2S audio

src/modules/ExternalNotificationModule.cpp

@@ -98,6 +98,13 @@ int32_t ExternalNotificationModule::runOnce()
                 LOG_INFO("%d ", i);
             }
             LOG_INFO("\n");
+#ifdef HAS_I2S
+            // GPIO0 is used as mclk for I2S audio and set to OUTPUT by the sound library
+            // T-Deck uses GPIO0 as trackball button, so restore the mode
+#if defined(T_DECK) || (defined(BUTTON_PIN) && BUTTON_PIN == 0)
+            pinMode(0, INPUT);
+#endif
+#endif
             isNagging = false;
             return INT32_MAX; // save cycles till we're needed again
         }