`rubi`: reduce firmware size (#24170)

keyboards/rubi/keyboard.json

@@ -22,6 +22,9 @@
             "resync": true
         }
     },
+   "build": {
+      "lto": true
+   },
    "matrix_pins": {
       "cols": ["B3", "B2", "B1", "F7"],
       "rows": ["F0", "F1", "F4", "F5", "F6"]