Move last bootscreen delay to end of setup (#21665)

Marlin/src/core/utility.h

@@ -25,8 +25,12 @@
 #include "../core/types.h"
 #include "../core/millis_t.h"
 
-// Delay that ensures heaters and watchdog are kept alive
-void safe_delay(millis_t ms);
+void safe_delay(millis_t ms);           // Delay ensuring that temperatures are updated and the watchdog is kept alive.
+#if ENABLED(MARLIN_DEV_MODE)
+  void early_safe_delay(millis_t ms);   // Delay ensuring that the watchdog is kept alive. Can be used before the Temperature ISR starts.
+#else
+  inline void early_safe_delay(millis_t ms) { safe_delay(ms); }
+#endif
 
 #if ENABLED(SERIAL_OVERRUN_PROTECTION)
   void serial_delay(const millis_t ms);