Update to error_tracker 0.9

Includes amendments resulting from new events, and proper handling of
the muted attribute

mix.exs

@@ -171,7 +171,7 @@ defmodule MusicLibrary.MixProject do
       {:lazy_html, ">= 0.1.0", only: :test},
 
       # Prod error/perf tooling
-      {:error_tracker, "~> 0.7"},
+      {:error_tracker, "~> 0.9"},
       {:phoenix_live_dashboard, "~> 0.8.3"},
       {:recon, "~> 2.5"},
       {:telemetry_metrics, "~> 1.0"},