fix(proxy): 修复 gRPC服务的 SSLContext 初始化错误和日志打印问题

- 在 GrpcServer 类中添加异常堆栈打印，以便更好地调试问题
- 在 ProxyAndTlsProtocolNegotiator 类中修正 SSLContext 初始化错误日志

Signed-off-by: Async <raisinata@foxmail.com>

Author: EnableAsync

proxy/src/main/java/org/apache/rocketmq/proxy/grpc/GrpcServer.java

@@ -68,6 +68,7 @@ public void shutdown() {
 
             log.info("grpc server shutdown successfully.");
         } catch (Exception e) {
+            e.printStackTrace();
             log.error("Failed to shutdown grpc server", e);
         }
     }

proxy/src/main/java/org/apache/rocketmq/proxy/grpc/ProxyAndTlsProtocolNegotiator.java

@@ -84,7 +84,7 @@ public ProxyAndTlsProtocolNegotiator() {
             loadSslContext(null, null);
             log.info("SSLContext created for proxy grpc server");
         } catch (IOException | CertificateException e) {
-            log.error("SslContext init error", e);
+            log.error("SSLContext init error", e);
             throw new RuntimeException(e);
         }
     }