test: Exclude Storybook modules from test coverage

mix.exs

@@ -9,7 +9,13 @@ defmodule MedicalTranscription.MixProject do
       elixirc_paths: elixirc_paths(Mix.env()),
       start_permanent: Mix.env() == :prod,
       aliases: aliases(),
-      deps: deps()
+      deps: deps(),
+      test_coverage: [
+        ignore_modules: [
+          ~r"MedicalTranscriptionWeb.Storybook*",
+          ~r"Storybook.*"
+        ]
+      ]
     ]
   end