[Improve] fix empty line in config/plugin_config causes BUILD FAILURE

[chaos-cn]

If config/plugin_config has empty line

mvn dependency:get -DgroupId=org.apache.seatunnel -DartifactId= -Dversion=2.3.3 -Ddest=/opt/apache-seatunnel-2.3.3/connectors

BUILD FAILURE

Purpose of this pull request

Fix empty line in config/plugin_config causes BUILD FAILURE.
Increase program robustness.

Does this PR introduce any user-facing change?

No

How was this patch tested?

add empty line in config/plugin_config

Check list

• If any new Jar binary package adding in your PR, please add License Notice according
  New License Guide
• If necessary, please update the documentation to describe the new feature. https://github.com/apache/seatunnel/tree/dev/docs
• If you are contributing the connector code, please check that the following files are updated:
  1. Update change log that in connector document. For more details you can refer to connector-v2
  2. Update plugin-mapping.properties and add new connector information in it
  3. Update the pom file of seatunnel-dist
• Update the release-note.

[EricJoy2048]

@chaos-cn

[chaos-cn]

@chaos-cn

All checks have passed