Use updated lesson data when updating quiz (#2336)

* Use live lesson data when updating quiz

Using the `$_POST` data led to inconsistent results after updating to 5.0. This method is tied to `save_post` so the lesson data will be updated by the time it fires.

* Remove dead code in lesson class that was causing another error

includes/class-sensei-lesson.php

@@ -455,11 +455,15 @@ public function quiz_update( $post_id ) {
 
 		 // Sanitize and setup the post data
 		$_POST = stripslashes_deep( $_POST );
+
+		// Retrieve the update lesson.
+		$lesson = get_post( $post_id );
+
 		if ( isset( $_POST['quiz_id'] ) && ( 0 < absint( $_POST['quiz_id'] ) ) ) {
 			$quiz_id = absint( $_POST['quiz_id'] );
 		} // End If Statement
-		$post_title   = esc_html( $_POST['post_title'] );
-		$post_status  = esc_html( $_POST['post_status'] );
+		$post_title   = esc_html( $lesson->post_title );
+		$post_status  = esc_html( $lesson->post_status );
 		$post_content = '';
 
 		// Setup Query Arguments
@@ -2802,7 +2806,6 @@ public function lesson_save_question( $data = array(), $context = 'quiz' ) {
 		} // End If Statement
 
 		$post_title  = $question_text;
-		$post_author = $data['post_author'];
 		$post_status = 'publish';
 		$post_type   = 'question';
 		// Handle the extended question text