Filings UI: doesn't properly return to filing when logging in

If a user goes to a Filings URL (eg, to create or resume a filing) but is not logged in then they are redirected to a Login URL. However, the Return URL (that they should return to after successfully logging in) is invalid -- it should contain the original URL route and parameters, but these are not present.

Thus, the user will return to an invalid URL, may see an error, and then will be redirected to the Business Dashboard or to their Business Registry Dashboard (or another generic URL).

The impact is that the user will have to re-navigate to Filings UI to perform their filing.

However, users should not manually navigate to Filings UI for any reason -- they should be redirected there from a link/action in the Business Dashboard, and only if they are already logged in.

Perhaps we need to re-think what should happen if a user tried to go to Filings UI while not logged in... I'm thinking they should immediately go back to their Business Dashboard, instead of trying to log in.