feat(Field): imporve readonly cursor

src/field/index.less

@@ -43,6 +43,10 @@
       opacity: 1;
     }
 
+    &:read-only {
+      cursor: default;
+    }
+
     &--center {
       text-align: center;
     }

src/stepper/index.less

@@ -89,6 +89,10 @@
       -webkit-text-fill-color: @stepper-input-disabled-text-color; // fix disabled color in iOS
       opacity: 1;
     }
+
+    &:read-only {
+      cursor: default;
+    }
   }
 
   input[type="number"]::-webkit-inner-spin-button,