message: Add isOpen() to IModelDb to make async call safer to sync api in IModeDb.ts
diff: @@ -1677,6 +1677,8 @@ export class IModelDb extends IModel {
  importSchema(requestContext: ClientRequestContext | AuthorizedClientRequestContext, schemaFileName: string): Promise<void>;
  // @internal (undocumented)
  insertCodeSpec(codeSpec: CodeSpec): Id64String;
  + // @internal
  + readonly isOpen: boolean;
  readonly isReadonly: boolean;
  // @deprecated
  readonly isStandalone: boolean;
  