Issues with handling the azure B2C user flows

Expected Behavior

Let the user handle the query params that are inside the Url for configuration discovery with attached query params

[REQUIRED] Describe expected behavior

Given an URL with a query params (ex. https://login.microsofonline.com/{tenant}/v2.0?p=B2C_1_nfwSignIn) make the URL formulated to construct a valid URL (ex. https://login.microsofonline.com/{tenant}/v2.0/.well-known/openid-configuration?p=B2C_1_nfwSignIn)

Describe the problem

The Issue comes when you pass the URL as stated above the formulated URL is not a valid one given the concatenation that occurs on the file authorization_service_configuration.ts

Also see this reference from Azure documentation

[REQUIRED] Actual Behavior

On function fetchFromIssuer
Input https://login.microsofonline.com/{tenant}/v2.0?p=B2C_1_nfwSignIn
Returns https://login.microsofonline.com/{tenant}/v2.0?p=B2C_1_nfwSignIn/.well-known/openid-configuration

[REQUIRED] Steps to reproduce the behavior

Just place the URL https://login.microsofonline.com/{tenant}/v2.0?p=B2C_1_nfwSignIn in the fetchFromIssuer function, I'm using a 3rd party plugin that has a dependency on this repo ionic-appauth

[REQUIRED] Environment

• AppAuth-JS version: 1.3.1
• AppAuth-JS Environment (Node, Browser (UserAgent), ...): Ionic which I assume would be browser____
• Source code snippts (inline or JSBin)

This code resolves my issue but I'm not sure how to make a pull request

static fetchFromIssuer(openIdIssuerUrl: string, requestor?: Requestor):
      Promise<AuthorizationServiceConfiguration> {
    const searchForQueryParams = function(url: string) {
      let result;
      let queryOr: any = url.split('/');
      let query = queryOr[queryOr.length - 1].split('?');
      if (query.length > 1) {
        queryOr.splice(queryOr.length - 1, 1);
        queryOr = queryOr.join('/');
        result = [queryOr, `?${query[query.lenght - 1]}`];
      } else {
        result = [url, ''];
      }

      return result;
    };
    const newUrl = searchForQueryParams(openIdIssuerUrl);
    const fullUrl = `${newUrl[0]}/${WELL_KNOWN_PATH}/${OPENID_CONFIGURATION}${newUrl[1]}`;

    const requestorToUse = requestor || new JQueryRequestor();

    return requestorToUse
        .xhr<AuthorizationServiceConfigurationJson>({url: fullUrl, dataType: 'json', method: 'GET'})
        .then(json => new AuthorizationServiceConfiguration(json));
  }

Start in authorization_service_configuration.ts at fetchFromIssuer and reproduce the Azure B2C issuer URL with query parameters. Verify that the generated discovery URL inserts /.well-known/openid-configuration before the query string and preserves the query parameters, then confirm the existing configuration fetch still succeeds.