Forgot password sends redirect link

with reset password email.

This is so when users reset their password they are still
redirected to pages they were meant to visit.

This change was done specifically so everyone who is meant to see
broadcast tour sees it, but it will improve lives of all users
who wanted to visit a page on Notify but then had to reset
their password in the process.

app/main/views/forgot_password.py

@@ -1,4 +1,4 @@
-from flask import render_template
+from flask import render_template, request
 from notifications_python_client.errors import HTTPError
 
 from app import user_api_client
@@ -11,7 +11,7 @@ def forgot_password():
     form = ForgotPasswordForm()
     if form.validate_on_submit():
         try:
-            user_api_client.send_reset_password_url(form.email_address.data)
+            user_api_client.send_reset_password_url(form.email_address.data, next_string=request.args.get('next'))
         except HTTPError as e:
             if e.status_code == 404:
                 return render_template('views/password-reset-sent.html')

app/notify_client/user_api_client.py

@@ -165,9 +165,11 @@ class UserApiClient(NotifyAdminAPIClient):
         endpoint = '/user/{}/service/{}/permission'.format(user_id, service_id)
         self.post(endpoint, data=data)
 
-    def send_reset_password_url(self, email_address):
+    def send_reset_password_url(self, email_address, next_string=None):
         endpoint = '/user/reset-password'
         data = {'email': email_address}
+        if next_string:
+            data['next'] = next_string
         self.post(endpoint, data=data)
 
     def find_users_by_full_or_partial_email(self, email_address):