Only raise when not in CI

src/python_spectrometer/_plot_manager.py

@@ -86,7 +86,10 @@ class PlotManager:
             fig = plt.figure(**self.figure_kw)
 
         try:
-            if fig.canvas.required_interactive_framework is None:
+            if (
+                    fig.canvas.required_interactive_framework is None
+                    and not os.environ.get('GITLAB_CI', False)
+            ):
                 # https://github.com/matplotlib/matplotlib/issues/20281#issuecomment-846057011
                 raise RuntimeError('Please enable an interactive backend')
         except AttributeError: