Elixir 1.19: Replace ugly old logger config checks with config merging

Side note: Going up in log levels doesn't work properly.
 - debug->info works
 - info->debug does not work

test/pleroma/config/deprecation_warnings_test.exs

@@ -392,11 +392,12 @@ defmodule Pleroma.Config.DeprecationWarningsTest do
   describe "check_deprecated_logger_config" do
     setup do
       Application.put_env(:logger, :backends, [:console, {ExSyslogger, :ex_syslogger}])
-      Application.put_env(:logger, :console, level: :warning)
+      Application.put_env(:logger, :console, level: :debug)
 
       on_exit(fn ->
         Application.delete_env(:logger, :backends)
         Application.delete_env(:logger, :console)
+        :logger.update_handler_config(:default, :formatter, Logger.default_formatter())
       end)
     end
 
@@ -432,5 +433,22 @@ defmodule Pleroma.Config.DeprecationWarningsTest do
                `:default_formatter`. For more info visit: https://hexdocs.pm/logger/Logger.html#module-backends-and-backwards-compatibility
                """
     end
+
+    test "reconfigures logger" do
+      log =
+        capture_log(fn ->
+          Pleroma.Config.DeprecationWarnings.check_deprecated_logger_config()
+        end)
+
+      # Formatter has inconsitent color formatting order
+      assert log =~
+               """
+               Reconfiguring console Logger with deprecated configuration syntax.
+                 Handler configuration:
+                   [level: :debug]
+
+                 Formatter:
+               """
+    end
   end
 end