Fix timezone definition and handling across app

lib/music_library_web/live/collection_live/show.ex

@@ -25,7 +25,7 @@ defmodule MusicLibraryWeb.CollectionLive.Show do
     {:ok,
      socket
      |> assign(:current_section, :collection)
-     |> assign(:timezone, resolve_timezone!())
+     |> assign(:timezone, MusicLibrary.timezone())
      |> assign(:can_scrobble?, ScrobbleActivity.can_scrobble?())
      |> assign(:release_with_tracks, nil)}
   end
@@ -182,9 +182,4 @@ defmodule MusicLibraryWeb.CollectionLive.Show do
 
   defp title_segment(:show), do: gettext("Show")
   defp title_segment(:edit), do: gettext("Edit")
-
-  defp resolve_timezone! do
-    Application.get_env(:music_library, MusicLibraryWeb)
-    |> Keyword.fetch!(:timezone)
-  end
 end

lib/music_library_web/live/stats_live/index.ex

@@ -23,7 +23,7 @@ defmodule MusicLibraryWeb.StatsLive.Index do
 
     {:ok,
      socket
-     |> assign(:timezone, resolve_timezone!())
+     |> assign(:timezone, MusicLibrary.timezone())
      |> stream_configure(:recent_tracks,
        dom_id: fn track -> "track-#{track.scrobbled_at_uts}" end
      )
@@ -160,9 +160,4 @@ defmodule MusicLibraryWeb.StatsLive.Index do
     |> DateTime.from_unix!()
     |> DateTime.to_iso8601()
   end
-
-  defp resolve_timezone! do
-    Application.get_env(:music_library, MusicLibraryWeb)
-    |> Keyword.fetch!(:timezone)
-  end
 end