Oxia: TLS CA certificate chain validation fails with multi-certificate PEM bundles

Oxia is a metadata store and coordination system. Prior to 0.16.2, the trustedCertPool() function in the TLS configuration only parses the first PEM block from CA certificate files. When a CA bundle contains multiple certificates (e.g., intermediate + root CA), only the first certificate is loaded. This silently breaks certificate chain validation for mTLS. This vulnerability is fixed in 0.16.2.