Drop BETA postfix from Matter integration's title (#139816)

Drop BETA postfix from Matter title

Now that the whole Matter stack of Home Assistant is officially certified, we can drop the beta flag.

homeassistant/components/matter/manifest.json

@@ -1,6 +1,6 @@
 {
   "domain": "matter",
-  "name": "Matter (BETA)",
+  "name": "Matter",
   "after_dependencies": ["hassio"],
   "codeowners": ["@home-assistant/matter"],
   "config_flow": true,

homeassistant/generated/integrations.json

@@ -3640,7 +3640,7 @@
       "iot_class": "cloud_push"
     },
     "matter": {
-      "name": "Matter (BETA)",
+      "name": "Matter",
       "integration_type": "hub",
       "config_flow": true,
       "iot_class": "local_push"