report user_role when submitting error form

We have a shared error form partial that we use for various
response codes that we handle in the Canvas app. Support wanted
to mimic our already existing behavior found in our Help Dialog.
This change includes the user's current roles in the POST
to generate an ErrorReport; if there is a current user session.
We give the opportunity to submit comments for things like 404
or 500 errors that the app handles and that's where this change
comes into play.

closes FOO-490
flag = none

test plan:
 * The easiest way to test this commit out is to trigger a handled
   500 error. I twiddled with some account settings code to make it
   happen.
 * You should get a spiffy image of a spacecraft and something along
   the lines of "Page Error", "Something broke unexpectedly"
 * There will be a "Click here to tell us what happened link"
 * Open up DevTools and head on over to the Network tab
 * Fill out the input and click the "Send Comments" button to submit
   the form
 * Inspect your network traffic and find the request to error_reports
 * Verify the Form Data includes the param "error[user_roles]"
   and it includes a comma seperated list of user roles
 * Find the associated ErrorReport for that submission /error_reports
 * Ensure it includes an optional data key for `user_roles:`
   below `type`, with the same comma seperated values that you
   inspected above

Change-Id: I5e014b599e481e27e9a66683d038e6270fa50b1d
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/242809
Tested-by: Service Cloud Jenkins <svc.cloudjenkins@instructure.com>
QA-Review: Ahmad Amireh <ahmad@instructure.com>
Product-Review: Ahmad Amireh <ahmad@instructure.com>
Reviewed-by: Charley Kline <ckline@instructure.com>
Reviewed-by: Simon Williams <simon@instructure.com>

app/views/shared/errors/_error_form.html.erb

@@ -26,6 +26,7 @@
     <%= text_area :error, :comments, :style => "width: 100%; height: 100px; border: 1px solid #888;" %>
     <% if @current_user %>
       <%= before_label('email_optional', %{Email (optional)}) %>
+      <%= hidden_field :error, :user_roles, :value => @current_user.try(:roles, @domain_root_account).join(',') %>
     <% else %>
       <%= before_label('email_required', %{Email (required)}) %>
     <% end %>

spec/controllers/errors_controller_spec.rb

@@ -46,11 +46,13 @@ describe ErrorsController do
         error: {
           url: "someurl",
           message: "BigError",
-          email: "testerrors42@example.com"
+          email: "testerrors42@example.com",
+          user_roles: "user,student"
         }
       }
       assert_recorded_error
       expect(ErrorReport.last.email).to eq("testerrors42@example.com")
+      expect(ErrorReport.last.data["user_roles"]).to eq("user,student")
     end
 
     it "doesnt need authentication" do

spec/views/shared/errors/_error_form.html.erb_spec.rb

@@ -25,6 +25,7 @@ describe "/shared/errors/_error_form" do
     view_context
     render :partial => "shared/errors/error_form"
     expect(response).not_to be_nil
+    expect(response).to include("error[user_roles]")
   end
 end