isWebSearchProviderAvailable function
Whether provider can serve searches given secrets: keyless providers
are always available, keyed ones need their non-empty key.
Implementation
bool isWebSearchProviderAvailable(
WebSearchProvider provider,
Map<String, String> secrets,
) {
final keyName = provider.apiKeyName;
if (keyName == null) return true;
return secrets[keyName]?.isNotEmpty ?? false;
}