Better error when using Mogrify

Hardcoding that the command isn't available is wrong. We check it on startup.

lib/pleroma/upload/filter/heif_to_jpeg.ex

@@ -22,7 +22,7 @@ defmodule Pleroma.Upload.Filter.HeifToJpeg do
       {:ok, :filtered, %Upload{upload | name: name, path: path, content_type: "image/jpeg"}}
     rescue
       e in ErlangError ->
-        {:error, "mogrify error: #{inspect(e)}"}
+        {:error, "#{__MODULE__}: #{inspect(e)}"}
     end
   end
 

lib/pleroma/upload/filter/mogrifun.ex

@@ -45,7 +45,7 @@ defmodule Pleroma.Upload.Filter.Mogrifun do
       {:ok, :filtered}
     rescue
       _e in ErlangError ->
-        {:error, "mogrify command not found"}
+        {:error, "#{__MODULE__}: #{inspect(e)}"}
     end
   end
 

lib/pleroma/upload/filter/mogrify.ex

@@ -15,7 +15,7 @@ defmodule Pleroma.Upload.Filter.Mogrify do
       {:ok, :filtered}
     rescue
       _e in ErlangError ->
-        {:error, "mogrify command not found"}
+        {:error, "#{__MODULE__}: #{inspect(e)}"}
     end
   end