backup fails despite plugins are available

i got the plugin showing up. facing two errors even after referring the [troubleshooting](https://cloudnative-pg.io/plugin-barman-cloud/docs/troubleshooting/) guide.

found two issues:
1) continous backup status is `OK` . tried basebackup and got requested plugin is not available: [barman-cloud.cloudnative-pg.io](http://barman-cloud.cloudnative-pg.io/) error. plugin status show as below on cnpg status for the cluster.

Name Version Status Reported Operator Capabilities
---- ------- ------ ------------------------------
barman-cloud.cloudnative-pg.io 0.9.0 N/A Reconciler Hooks, Lifecycle Service

2) adding retentionPolicy on barmanstore Yaml and tried to rid off `No recovery window information found in ObjectStore 'db-backupstore' for server 'fusdb'` error. it does not make a difference.

cloudnative PG v1.27.1

从链接的故障排查指南以及针对插件版本 0.9.0 报告的 CNPG 状态输出开始。针对 CloudNativePG v1.27.1 中报告的 recovery-window 错误，检查 basebackup 失败和 BarmanStore 的 retentionPolicy 配置；完成的标准是确定一个可复现的原因，或记录缺失的配置或兼容性细节。

由索引模型根据 Issue 内容生成。