[Bug][Manager] NPE is thrown in the cache configuration of DataProxy

[healchow]

What happened

See the error log:

2022-11-11 16:50:10.893 -ERROR [Timer-0] .s.r.DataProxyConfigRepository:311 - null 
java.lang.NullPointerException: null
        at org.apache.inlong.manager.service.repository.DataProxyConfigRepository.fromJson(DataProxyConfigRepository.java:302) ~[manager-service-1.5.0-SNAPSHOT.jar:1.5.0-SNAPSHOT]
        at org.apache.inlong.manager.service.repository.DataProxyConfigRepository.lambda$reloadInlongId$9(DataProxyConfigRepository.java:337) ~[manager-service-1.5.0-SNAPSHOT.jar:1.5.0-SNAPSHOT]
        at java.util.HashMap.forEach(HashMap.java:1290) ~[?:1.8.0_322]
        at org.apache.inlong.manager.service.repository.DataProxyConfigRepository.reloadInlongId(DataProxyConfigRepository.java:337) ~[manager-service-1.5.0-SNAPSHOT.jar:1.5.0-SNAPSHOT]
        at org.apache.inlong.manager.service.repository.DataProxyConfigRepository.reload(DataProxyConfigRepository.java:219) ~[manager-service-1.5.0-SNAPSHOT.jar:1.5.0-SNAPSHOT]
        at org.apache.inlong.common.pojo.dataproxy.RepositoryTimerTask.run(RepositoryTimerTask.java:40) ~[inlong-common-1.5.0-SNAPSHOT.jar:1.5.0-SNAPSHOT]
        at java.util.TimerThread.mainLoop(Timer.java:555) ~[?:1.8.0_322]
        at java.util.TimerThread.run(Timer.java:505) ~[?:1.8.0_322]

What you expected to happen

Should not throw the NPE.

How to reproduce

Environment

No response

InLong version

master

InLong Component

InLong Manager

Are you willing to submit PR?

• Yes, I am willing to submit a PR!

Code of Conduct

• I agree to follow this project's Code of Conduct