Fix aria label icon name (#5992)

src/components/ha-icon-button.ts

@@ -25,7 +25,7 @@ export class HaIconButton extends LitElement {
   protected render(): TemplateResult {
     return html`
       <mwc-icon-button
-        .label=${this.label || this.icon}
+        .label=${this.label}
         ?disabled=${this.disabled}
         @click=${this._handleClick}
       >

src/panels/lovelace/hui-root.ts

@@ -183,7 +183,7 @@ class HUIRoot extends LitElement {
                   ${this._conversation(this.hass.config.components)
                     ? html`
                         <ha-icon-button
-                          aria-label="Start conversation"
+                          label="Start conversation"
                           icon="hass:microphone"
                           @click=${this._showVoiceCommandDialog}
                         ></ha-icon-button>