feat: Add a blocklyNumberField CSS class to number fields (#8414)

* feat: Add a blocklyNumberField CSS class to number fields https://github.com/google/blockly/issues/8313

* feat: add 'blocklyNumberField' CSS class to FieldNumber Fixes https://github.com/google/blockly/issues/8313

core/field_number.ts

@@ -19,6 +19,7 @@ import {
   FieldInputValidator,
 } from './field_input.js';
 import * as aria from './utils/aria.js';
+import * as dom from './utils/dom.js';
 
 /**
  * Class for an editable number field.
@@ -307,6 +308,19 @@ export class FieldNumber extends FieldInput<number> {
     return htmlInput;
   }
 
+  /**
+   * Initialize the field's DOM.
+   *
+   * @override
+   */
+
+  public override initView() {
+    super.initView();
+    if (this.fieldGroup_) {
+      dom.addClass(this.fieldGroup_, 'blocklyNumberField');
+    }
+  }
+
   /**
    * Construct a FieldNumber from a JSON arg object.
    *