[mqtt] Don't wait for connection unless configured to (#8933)

esphome/components/mqtt/__init__.py

@@ -68,6 +68,7 @@ def AUTO_LOAD():
 
 CONF_DISCOVER_IP = "discover_ip"
 CONF_IDF_SEND_ASYNC = "idf_send_async"
+CONF_WAIT_FOR_CONNECTION = "wait_for_connection"
 
 
 def validate_message_just_topic(value):
@@ -298,6 +299,7 @@ CONFIG_SCHEMA = cv.All(
                 }
             ),
             cv.Optional(CONF_PUBLISH_NAN_AS_NONE, default=False): cv.boolean,
+            cv.Optional(CONF_WAIT_FOR_CONNECTION, default=False): cv.boolean,
         }
     ),
     validate_config,
@@ -453,6 +455,8 @@ async def to_code(config):
 
     cg.add(var.set_publish_nan_as_none(config[CONF_PUBLISH_NAN_AS_NONE]))
 
+    cg.add(var.set_wait_for_connection(config[CONF_WAIT_FOR_CONNECTION]))
+
 
 MQTT_PUBLISH_ACTION_SCHEMA = cv.Schema(
     {