🐛 Fix MPC compile (#24049)

Followup to #23984, #23751

Co-authored-by: Scott Lahteine <thinkyhead@users.noreply.github.com>

Marlin/src/gcode/temp/M306.cpp

@@ -69,7 +69,9 @@ void GcodeSuite::M306_report(const bool forReplay/*=true*/) {
     SERIAL_ECHOPAIR_F(" C", constants.block_heat_capacity, 2);
     SERIAL_ECHOPAIR_F(" R", constants.sensor_responsiveness, 4);
     SERIAL_ECHOPAIR_F(" A", constants.ambient_xfer_coeff_fan0, 4);
-    SERIAL_ECHOLNPAIR_F(" F", constants.ambient_xfer_coeff_fan0 + constants.fan255_adjustment, 4);
+    #if ENABLED(MPC_INCLUDE_FAN)
+      SERIAL_ECHOLNPAIR_F(" F", constants.ambient_xfer_coeff_fan0 + constants.fan255_adjustment, 4);
+    #endif
   }
 }
 

Marlin/src/lcd/menu/menu_advanced.cpp

@@ -366,7 +366,7 @@ void menu_backlash();
           MPC_EDIT_ITEMS(e);
           END_MENU();
         };
-        #define MPC_ENTRY(N) SUBMENU_N(N, MSG_MPC_EDIT, []{ mpc_edit_hotend(MenuItemBase::itemIndex); });
+        #define MPC_ENTRY(N) SUBMENU_N(N, MSG_MPC_EDIT, [&]{ mpc_edit_hotend(MenuItemBase::itemIndex); });
       #else
         #define MPC_ENTRY MPC_EDIT_ITEMS
       #endif

buildroot/tests/BIGTREE_GTR_V1_0

@@ -38,7 +38,7 @@ opt_set MOTHERBOARD BOARD_BTT_GTR_V1_0 SERIAL_PORT -1 \
         MPC_SENSOR_RESPONSIVENESS '{ 0.22f, 0.22f, 0.22f }' \
         MPC_AMBIENT_XFER_COEFF '{ 0.068f, 0.068f, 0.068f }' \
         MPC_AMBIENT_XFER_COEFF_FAN255 '{ 0.097f, 0.097f, 0.097f }'
-opt_enable SWITCHING_TOOLHEAD TOOL_SENSOR MPCTEMP
+opt_enable SWITCHING_TOOLHEAD TOOL_SENSOR MPCTEMP MPC_EDIT_MENU MPC_AUTOTUNE_MENU
 opt_disable PIDTEMP
 exec_test $1 $2 "BigTreeTech GTR | MPC | Switching Toolhead | Tool Sensors" "$3"