async _doFetch(url) {
    const response = await fetch(url, {
      headers: this.#getHeaders(),
    });
    if (!response.ok) {
      throw new Error(`Failed to fetch ${url}: ${response.status}`);
    }
    return response.json();
  }
Generate the full chunkSource for a specific Confluence page so that we can resync it later.
This data is encrypted into a single `payload` query param so we can replay credentials later
since this was encrypted with the systems persistent password and salt.
@param {number} pageId
@param {import("../../EncryptionWorker").EncryptionWorker} encryptionWorker
@returns {string}