Fix some more missing #pragma onces (#20241)

keyboards/gboards/engine/keymap_engine.h

@@ -7,6 +7,8 @@
  * With this disgusting bodge, you can just edit your .defs and compile!
  */
 
+#pragma once
+
 // Clear all X Macros
 #define PRES BLANK
 #define KEYS BLANK

keyboards/gboards/g/config_default.h

@@ -1,3 +1,5 @@
+#pragma once
+
 #include "engine.h"
 
 // Configuration options for the engine

keyboards/gboards/g/keymap_combo.h

@@ -1,3 +1,5 @@
+#pragma once
+
 // Keymap helpers
 // define reference layers per layer.
 #define REF_LAYER_FOR_LAYER(LAYER, REF_LAYER)   \

keyboards/gboards/g/keymap_engine.h

@@ -6,6 +6,9 @@
  * using a external generator (Like is done for the ASETNIOP base keymaps)
  * With this disgusting bodge, you can just edit your .defs and compile!
  */
+
+#pragma once
+
 #include "g/engine.h"
 
 // Clear all X Macros