Fix issues made in #7614 (#7622)

* Fix issues made in #7614

* Flip cases

* Remove caching of the debug settings

---------

Co-authored-by: Oliver <oliver.henry.walters@gmail.com>

src/backend/InvenTree/plugin/builtin/labels/label_sheet.py

@@ -75,12 +75,6 @@ class InvenTreeLabelSheetPlugin(LabelPrintingMixin, SettingsMixin, InvenTreePlug
     }
 
     PrintingOptionsSerializer = LabelPrintingOptionsSerializer
-    debug = None
-
-    def in_debug_mode(self):
-        """Check if the plugin is printing in debug mode."""
-        if self.debug is None:
-            self.debug = str2bool(self.get_setting('DEBUG'))
 
     def print_labels(
         self, label: LabelTemplate, output: LabelOutput, items: list, request, **kwargs
@@ -149,14 +143,15 @@ def print_labels(
         # Render to a single HTML document
         html_data = self.wrap_pages(pages, **document_data)
 
-        if self.in_debug_mode():
+        if str2bool(self.get_setting('DEBUG')):
+            # In debug mode return with the raw HTML
+            output.output = ContentFile(html_data, 'labels.html')
+        else:
             # Render HTML to PDF
             html = weasyprint.HTML(string=html_data)
             document = html.render().write_pdf()
 
             output.output = ContentFile(document, 'labels.pdf')
-        else:
-            output.output = ContentFile(html_data, 'labels.html')
 
         output.progress = 100
         output.complete = True