Fix Gun connection supervisor logic error

This was recently changed to solve a Dialyzer error, but the replacement logic was faulty as "retry" would only be compared to :error and not have its truthiness evaluated.

The original logic was also faulty as it returned {:error, :pool_full} even retry was true. It never retried when the pool was full.

changelog.d/gun_pool.fix

@@ -0,0 +1 @@
+Fix logic error in Gun connection pooling which prevented retries even when the worker was launched with retry = true

lib/pleroma/gun/connection_pool/worker_supervisor.ex

@@ -21,7 +21,9 @@ defmodule Pleroma.Gun.ConnectionPool.WorkerSupervisor do
   def start_worker(opts, retry \\ false) do
     case DynamicSupervisor.start_child(__MODULE__, {Pleroma.Gun.ConnectionPool.Worker, opts}) do
       {:error, :max_children} ->
-        if Enum.any?([retry, free_pool()], &match?(&1, :error)) do
+        funs = [fn -> !retry end, fn -> match?(:error, free_pool()) end]
+
+        if Enum.any?(funs, fn fun -> fun.() end) do
           :telemetry.execute([:pleroma, :connection_pool, :provision_failure], %{opts: opts})
           {:error, :pool_full}
         else