Prefer nothing over empty templates (#15633)

src/panels/lovelace/entity-rows/hui-weather-entity-row.ts

@@ -4,7 +4,7 @@ import {
   html,
   LitElement,
   PropertyValues,
-  TemplateResult,
+  nothing,
 } from "lit";
 import { customElement, property, state } from "lit/decorators";
 import { classMap } from "lit/directives/class-map";
@@ -50,9 +50,9 @@ class HuiWeatherEntityRow extends LitElement implements LovelaceRow {
     return hasConfigOrEntityChanged(this, changedProps);
   }
 
-  protected render(): TemplateResult {
+  protected render() {
     if (!this.hass || !this._config) {
-      return html``;
+      return nothing;
     }
 
     const stateObj = this.hass.states[this._config.entity] as WeatherEntity;