The `FETCH_ERROR` document is used when we are unable to retrieve a
document (except for 404 errors), which includes when there is no
internet connection. Using the `<current-location>` element in the
document's template to show the path of the page we failed to retrieve
assumes that the element's bundle is available (e.g. cached by the SW)
or can be fetched from the server.
When none of these conditions is met, the `DocViewer` is unable to
prepare the document and fails, never showing the `FETCH_ERROR` page to
the user.
Furthermore, the path we are looking to retrieve via
`<current-location>` is essentially the document ID, which we already
have. Thus, loading and instantiating a whole component just for that is
overkill.
This commit addresses both issues by getting rid of the
`<current-location>` component and directly embedding the document ID
into the `FETCH_ERROR` content.
PR Close#27250