fix(orchestrator): drop google_protos dep conflicting with protobuf builtins

The google_protos package redefines modules (Google.Protobuf.Any, etc.)
already provided by protobuf ~> 0.13, causing --warnings-as-errors to
fail the production release build.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Signed-off-by: Tyler J King <tking@guildhouse.dev>

apps/guildhall_orchestrator/mix.exs

@@ -31,7 +31,6 @@ defmodule Guildhall.Orchestrator.MixProject do
       {:jason, "~> 1.4"},
       {:grpc, "~> 0.9"},
       {:protobuf, "~> 0.13"},
-      {:google_protos, "~> 0.4"},
       {:toml, "~> 0.7"}
     ]
   end