EntityBase: Move ObjectId to Flash (#4569)

* Move EntityBase Object Id from memory to flash.

* Sprinkler use common `setup_entity` method.

* Remove `EntityBase` from Sprinkler.

* Support for entity names set to None

* change so gh PR picks up commit.

---------

Co-authored-by: Your Name <you@example.com>
Co-authored-by: Jesse Hills <3060199+jesserockz@users.noreply.github.com>

esphome/cpp_helpers.py

@@ -20,6 +20,7 @@ from esphome.types import ConfigType, ConfigFragmentType
 from esphome.cpp_generator import add, get_variable
 from esphome.cpp_types import App
 from esphome.util import Registry, RegistryEntry
+from esphome.helpers import snake_case, sanitize
 
 
 _LOGGER = logging.getLogger(__name__)
@@ -101,6 +102,10 @@ async def register_parented(var, value):
 async def setup_entity(var, config):
     """Set up generic properties of an Entity"""
     add(var.set_name(config[CONF_NAME]))
+    if not config[CONF_NAME]:
+        add(var.set_object_id(sanitize(snake_case(CORE.friendly_name))))
+    else:
+        add(var.set_object_id(sanitize(snake_case(config[CONF_NAME]))))
     add(var.set_disabled_by_default(config[CONF_DISABLED_BY_DEFAULT]))
     if CONF_INTERNAL in config:
         add(var.set_internal(config[CONF_INTERNAL]))