Bug of ConnectionControlManager: During initialization, when no connection limit rules are found, it should use RuleParser to create a blank rule, rather than directly creating a ConnectionControlRule. #12397
Description
Describe the bug
The ConnectionControlManager class has a bug: During initialization, when no connection limit rules are found, it should use RuleParser to create a blank rule, rather than directly creating a ConnectionControlRule.
ConnectionControlManager类存在bug:初始化时，当查询不到链接限制规则时，应该使用RuleParser来新建空白规则，而不是直接创建ConnectionControlRule，这会对扩展性造成损伤
Expected behavior
Use RuleParser to create a blank rule
Actually behavior
directly creating a ConnectionControlRule
How to Reproduce
Steps to reproduce the behavior:
- Go to '...'
- Click on '....'
- Scroll down to '....'
- See errors
Desktop (please complete the following information):
- OS: [e.g. Centos]
- Version [e.g. nacos-server 1.3.1, nacos-client 1.3.1]
- Module [e.g. naming/config]
- SDK [e.g. original, spring-cloud-alibaba-nacos, dubbo]
Additional context
Add any other context about the problem here.