Revert "FIX: Set default value for poll result field (#10044)"

This reverts commit 40de535224.

Sadly this appears to break the JS test suite

plugins/poll/assets/javascripts/controllers/poll-ui-builder.js.es6

@@ -350,7 +350,6 @@ export default Controller.extend({
       pollStep: 1,
       autoClose: false,
       chartType: BAR_CHART_TYPE,
-      pollResult: this.alwaysPollResult,
       pollGroups: null,
       date: moment()
         .add(1, "day")

plugins/poll/test/javascripts/controllers/poll-ui-builder-test.js.es6

@@ -320,11 +320,6 @@ test("staff_only option is not present for non-staff", function(assert) {
   );
 });
 
-test("poll result is always by default", function(assert) {
-  const controller = this.subject();
-  assert.equal(controller.pollResult, "always");
-});
-
 test("staff_only option is present for staff", function(assert) {
   const controller = this.subject();
   controller.currentUser = { staff: true };