message: Add column.requiredErrorText property into MatrixDropdown/dynamic questions,
diff: @@ -226,6 +226,15 @@ export class MatrixDropdownColumn extends Base implements ILocalizableOwner {
  public set isRequired(val: boolean) {
  this.templateQuestion.isRequired = val;
  }
  + public get requiredErrorText(): string {
  + return this.templateQuestion.requiredErrorText;
  + }
  + public set requiredErrorText(val: string) {
  + this.templateQuestion.requiredErrorText = val;
  + }
  + get locRequiredErrorText(): LocalizableString {
  + return this.templateQuestion.locRequiredErrorText;
  + }
  public get readOnly(): boolean {
  return this.templateQuestion.readOnly;
  }
  @@ -1249,6 +1258,10 @@ JsonObject.metaData.addClass(
  },
  { name: "colCount", default: -1, choices: [-1, 0, 1, 2, 3, 4] },
  "isRequired:boolean",
  + {
  + name: "requiredErrorText:text",
  + serializationProperty: "locRequiredErrorText"
  + },
  "hasOther:boolean",
  "readOnly:boolean",
  "minWidth",
  