Increase number of MMU load tries, so the same number of retries are done without cutter as before enabling cutter.

Firmware/mmu.cpp

@@ -1566,7 +1566,7 @@ void mmu_continue_loading(bool blocking)
     };
     Ls state = Ls::Enter;
 
-    const uint_least8_t max_retry = 2;
+    const uint_least8_t max_retry = 3;
     uint_least8_t retry = 0;
 
     while (!success)