Add placeholder text for ha-selector-device (#27551)

* Add placeholder text for ha-selector-device

Added for:
- ha-selector-device
- ha-selector-entity

src/components/ha-selector/ha-selector-entity.ts

@@ -29,6 +29,8 @@ export class HaEntitySelector extends LitElement {
 
   @property() public helper?: string;
 
+  @property() public placeholder?: any;
+
   @property({ type: Boolean }) public disabled = false;
 
   @property({ type: Boolean }) public required = true;
@@ -69,6 +71,7 @@ export class HaEntitySelector extends LitElement {
         .excludeEntities=${this.selector.entity?.exclude_entities}
         .entityFilter=${this._filterEntities}
         .createDomains=${this._createDomains}
+        .placeholder=${this.placeholder}
         .disabled=${this.disabled}
         .required=${this.required}
         allow-custom-entity
@@ -86,6 +89,7 @@ export class HaEntitySelector extends LitElement {
         .reorder=${this.selector.entity.reorder ?? false}
         .entityFilter=${this._filterEntities}
         .createDomains=${this._createDomains}
+        .placeholder=${this.placeholder}
         .disabled=${this.disabled}
         .required=${this.required}
       ></ha-entities-picker>