Allow entity names to be set to None (#4607)

* Allow entity names to be set to None so they take on the device friendly_name automatically

* Use empty

esphome/config_validation.py

@@ -1514,6 +1514,8 @@ def _entity_base_validator(config):
         config[CONF_NAME] = id.id
         config[CONF_INTERNAL] = True
         return config
+    if config[CONF_NAME] is None:
+        config[CONF_NAME] = ""
     return config
 
 
@@ -1573,6 +1575,23 @@ def validate_registry_entry(name, registry):
     return validator
 
 
+def none(value):
+    if value in ("none", "None"):
+        return None
+    if boolean(value) is False:
+        return None
+    raise Invalid("Must be none")
+
+
+def requires_friendly_name(message):
+    def validate(value):
+        if CORE.friendly_name is None:
+            raise Invalid(message)
+        return value
+
+    return validate
+
+
 def validate_registry(name, registry):
     return ensure_list(validate_registry_entry(name, registry))
 
@@ -1632,7 +1651,15 @@ MQTT_COMMAND_COMPONENT_SCHEMA = MQTT_COMPONENT_SCHEMA.extend(
 
 ENTITY_BASE_SCHEMA = Schema(
     {
-        Optional(CONF_NAME): string,
+        Optional(CONF_NAME): Any(
+            All(
+                none,
+                requires_friendly_name(
+                    "Name cannot be None when esphome->friendly_name is not set!"
+                ),
+            ),
+            string,
+        ),
         Optional(CONF_INTERNAL): boolean,
         Optional(CONF_DISABLED_BY_DEFAULT, default=False): boolean,
         Optional(CONF_ICON): icon,