[Improvement] optimize TestUtils.httpGet in ShuffleServerGrpcTest.sendDataAndRequireBufferTest()

### Code of Conduct

- [X] I agree to follow this project's [Code of Conduct](https://www.apache.org/foundation/policies/conduct)

### Search before asking

- [X] I have searched in the [issues](https://github.com/apache/incubator-uniffle/issues?q=is%3Aissue) and found no similar issues.

### What would you like to be improved?

optimize TestUtils.httpGet in ShuffleServerGrpcTest.sendDataAndRequireBufferTest()

https://github.com/apache/incubator-uniffle/pull/1425#discussion_r1444150953

### How should we improve?

_No response_

### Are you willing to submit PR?

- [X] Yes I am willing to submit a PR!

Start with TestUtils.httpGet and ShuffleServerGrpcTest.sendDataAndRequireBufferTest, then read the linked pull request discussion for the requested optimization. Compare the current test behavior and HTTP helper usage; done means the test is optimized without changing its expected behavior.

Written by the indexing model from the issue text.