acceptance: disable Elixir tests

Elixir requires network to install dependencies. This can be changed
(painfully), but an upgrade on Elixir is causing even more problems. I'm
in favour of removing the acceptance (which I wrote) to fix this for now
as I have plentiful unit tests covering the same thing. Maybe someone
can come back to this if it's a large issue...

Release note: None

pkg/acceptance/adapter_test.go

@@ -56,6 +56,8 @@ func TestDockerJava(t *testing.T) {
 }
 
 func TestDockerElixir(t *testing.T) {
+	t.Skip("Elixir requires network to run, which can flake. When attempting to update this (#52341), the new Elixir version does not work with CRDB/TLS.")
+
 	s := log.Scope(t)
 	defer s.Close(t)