[Improve][Connector-V2] Optimize Milvus doc and e2e test case

[zhangshenghang]

Purpose of this pull request

1. Support configuring the COLLECTION parameter on the Sink
2. Add test code for auto create index.

• close [Bug] [milvus] index lost #9719

Does this PR introduce any user-facing change?

How was this patch tested?

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 plugin-mapping.properties and add new connector information in it
  2. Update the pom file of seatunnel-dist
  3. Add ci label in label-scope-conf
  4. Add e2e testcase in seatunnel-e2e
  5. Update connector plugin_config

[Hisoka-X]

Hi @zhangshenghang . I can not find how to fix index lost in this patch? Does this bug not exist?

[Hisoka-X]

Could you add create_index/load_collection/collection_description option into docs?