fix(测试跟踪): 选择Jira勾选第三方模板后再换其他平台模板，缺陷列表无法加载

--bug=1019902 --user=陈建星 【测试跟踪】项目中选择自定义的local缺陷模版，缺陷管理页刷不出来了 https://www.tapd.cn/55049933/s/1299371

test-track/backend/src/main/java/io/metersphere/service/PlatformPluginService.java

@@ -63,7 +63,7 @@ public class PlatformPluginService {
             return false;
         }
         PluginMetaInfo pluginMetaInfo = pluginManager.getPluginMetaInfoByKey(platform);
-        return pluginMetaInfo.isThirdPartTemplateSupport();
+        return pluginMetaInfo == null ? false : pluginMetaInfo.isThirdPartTemplateSupport();
     }
 
     public Platform getPlatform(String platformKey, String workspaceId) {