fix(web-search): restore SecretRef runtime compatibility for bundled providers (#68424)

Adds missing compatibility runtime path metadata for bundled SecretRef-capable web-search providers and keeps the manifest registry covered by a regression test.\n\nThanks @afurm!

extensions/google/openclaw.plugin.json

@@ -53,6 +53,9 @@
     "videoGenerationProviders": ["google"],
     "webSearchProviders": ["gemini"]
   },
+  "configContracts": {
+    "compatibilityRuntimePaths": ["tools.web.search.apiKey"]
+  },
   "configSchema": {
     "type": "object",
     "additionalProperties": false,