fix(common): Fix the FormattedExecutionResult.errors type

[pleunv]

https://github.com/enisdenjo/graphql-ws/releases/tag/v6.0.0 introduced a FormattedExecutionResult, however, its errors type seems to be incorrect as it's set to ReadonlyArray<FormattedExecutionResult> rather than ReadonlyArray<GraphQLFormattedError>:

/** @category Common */
export interface FormattedExecutionResult<
  Data = Record<string, unknown>,
  Extensions = Record<string, unknown>,
> {
  errors?: ReadonlyArray<FormattedExecutionResult> | undefined;
  data?: Data | null | undefined;
  hasNext?: boolean | undefined;
  extensions?: Extensions | undefined;
}

This is remediated by this PR.

[enisdenjo]

Oof what an oversight... Thanks!