ai-proxy: support custom openai provider (#1176)

Co-authored-by: Kent Dong <ch3cho@qq.com>

plugins/wasm-go/extensions/ai-proxy/provider/baidu.go

@@ -34,6 +34,9 @@ type baiduProviderInitializer struct {
 }
 
 func (b *baiduProviderInitializer) ValidateConfig(config ProviderConfig) error {
+	if config.apiTokens == nil || len(config.apiTokens) == 0 {
+		return errors.New("no apiToken found in provider config")
+	}
 	return nil
 }