Catch Throwable rather than Exception when sending heartbeat.

Signed-off-by: Carpenter Lee <hooleeucas@163.com>

sentinel-transport/sentinel-transport-common/src/main/java/com/alibaba/csp/sentinel/transport/init/HeartbeatSenderInitFunc.java

@@ -62,7 +62,7 @@ public class HeartbeatSenderInitFunc implements InitFunc {
                     public void run() {
                         try {
                             sender.sendHeartbeat();
-                        } catch (Exception e) {
+                        } catch (Throwable e) {
                             e.printStackTrace();
                             RecordLog.info("[HeartbeatSender] Send heartbeat error", e);
                         }