[lvgl] Fix setting empty text (#13494)

esphome/components/lvgl/widgets/label.py

@@ -32,7 +32,7 @@ class LabelType(WidgetType):
 
     async def to_code(self, w: Widget, config):
         """For a text object, create and set text"""
-        if value := config.get(CONF_TEXT):
+        if (value := config.get(CONF_TEXT)) is not None:
             await w.set_property(CONF_TEXT, await lv_text.process(value))
         await w.set_property(CONF_LONG_MODE, config)
         await w.set_property(CONF_RECOLOR, config)

tests/components/lvgl/lvgl-package.yaml

@@ -197,6 +197,9 @@ lvgl:
         - lvgl.label.update:
             id: msgbox_label
             text: Unloaded
+        - lvgl.label.update:
+            id: msgbox_label
+            text: "" # Empty text
       on_all_events:
         logger.log:
           format: "Event %s"