Fix bug: pass the bs_request superseded object, not the number

src/api/app/controllers/webui/request_controller.rb

@@ -542,7 +542,7 @@ def prepare_request_data
     @staging_status = staging_status(@bs_request, target_project) if Staging::Workflow.find_by(project: target_project)
 
     # Collecting all issues in a hash. Each key is the issue name and the value is a hash containing all the issue details.
-    @issues = @action.webui_sourcediff({ diff_to_superseded: @diff_to_superseded_id, cacheonly: 1 }).reduce({}) { |accumulator, sourcediff| accumulator.merge(sourcediff.fetch('issues', {})) }
+    @issues = @action.webui_sourcediff({ diff_to_superseded: @diff_to_superseded, cacheonly: 1 }).reduce({}) { |accumulator, sourcediff| accumulator.merge(sourcediff.fetch('issues', {})) }
 
     # retrieve a list of all package maintainers that are assigned to at least one target package
     @package_maintainers = target_package_maintainers