fix(config_file): remove unnecessary nil checks

Reworked testing code to not need this

Author: cameronr

lua/opencode/config_file.lua

@@ -9,10 +9,6 @@ function M.get_opencode_config()
   if not M.config_promise then
     local state = require('opencode.state')
     M.config_promise = state.api_client:get_config()
-    -- shouldn't normally happen but prevents error in replay tester
-    if not M.config_promise then
-      return
-    end
   end
   return M.config_promise:wait() --[[@as OpencodeConfigFile|nil]]
 end
@@ -30,11 +26,7 @@ end
 function M.get_opencode_providers()
   if not M.providers_promise then
     local state = require('opencode.state')
-    -- shouldn't normally happen but prevents error in replay tester
     M.providers_promise = state.api_client:list_providers()
-    if not M.providers_promise then
-      return
-    end
   end
   return M.providers_promise:wait() --[[@as OpencodeProvidersResponse|nil]]
 end