Configuration:
- PDF.js version: 2.0.550

Steps to reproduce the problem:
1. Render document in SVG mode `renderMode="svg"`

What is the expected behavior? (add screenshot)
Rendering annotations same way as they rendered on canvas

What went wrong? (add screenshot)
```
Warning: Unimplemented operator beginAnnotations
Warning: Unimplemented operator endAnnotations
```
if (Array.isArray(formValue)) {
      return formValue
        .filter(item => isString(item))
        .map(item => stringToPDFString(item));
    } else if (isName(formValue)) {
      return stringToPDFString(formValue.name);
    } else if (isString(formValue)) {
      return stringToPDFString(formValue);
    }
    return null;
  }
  /**
   * Check if a provided field flag is set.
   *
   * @public
   * @memberof WidgetAnnotation
   * @param {number} flag - Hexadecimal representation for an annotation
   *                        field characteristic
   * @returns {boolean}
   * @see {@link shared/util.js}
   */
  hasFieldFlag(flag) {
    return !!(this.data.fieldFlags & flag);
  }
  getOperatorList(evaluator, task, renderForms, annotationStorage) {