fetch env without raise

apps/explorer/lib/explorer/application.ex

@@ -56,9 +56,7 @@ defmodule Explorer.Application do
   end
 
   defp should_start?(process) do
-    :explorer
+    Application.get_env(:explorer, process, [])[:enabled] == true
-    |> Application.fetch_env!(process)
-    |> Keyword.fetch!(:enabled)
   end
 
   defp configure(process) do

apps/explorer/lib/explorer/exchange_rates/exchange_rates.ex

@@ -135,8 +135,6 @@ defmodule Explorer.ExchangeRates do
   end
 
   defp enabled? do
-    :explorer
+    Application.get_env(:explorer, __MODULE__, [])[:enabled] == true
-    |> Application.fetch_env!(__MODULE__)
-    |> Keyword.fetch!(:enabled)
   end
 end

apps/explorer/lib/explorer/known_tokens/known_tokens.ex

@@ -134,8 +134,6 @@ defmodule Explorer.KnownTokens do
   end
 
   defp enabled? do
-    :explorer
+    Application.get_env(:explorer, __MODULE__, [])[:enabled] == true
-    |> Application.fetch_env!(__MODULE__)
-    |> Keyword.fetch!(:enabled)
   end
 end