Fixes duplicate "Device info" section name when viewing Matter devices. (#28984)

ha-device-info-matter: rename 'Device info' to 'Matter info'

Fixes duplicate "Device info" section name when viewing Matter devices.
The nested expansion panel now displays "Matter info" consistent with
other integrations (e.g., ZHA uses "Zigbee info", Z-Wave uses "Z-Wave info").

Also adds a gallery demo for testing the component.

src/panels/config/devices/device-detail/integration-elements/matter/ha-device-info-matter.ts

@@ -51,7 +51,7 @@ export class HaDeviceInfoMatter extends SubscribeMixin(LitElement) {
     return html`
       <ha-expansion-panel
         .header=${this.hass.localize(
-          "ui.panel.config.matter.device_info.device_info"
+          "ui.panel.config.matter.device_info.matter_info"
         )}
       >
         <div class="row">

src/translations/en.json

@@ -6899,7 +6899,7 @@
             "unknown": "Unknown"
           },
           "device_info": {
-            "device_info": "Device info",
+            "matter_info": "Matter info",
             "node_id": "Node ID",
             "network_type": "Network type",
             "node_type": "Device type",