[Bug]: http-client-java, Builder didn't set httpClient for unbranded

[weidongxu-microsoft]

Describe the bug

We didn't set httpClient from Builder to HttpPipelineBuilder httpPipelineBuilder in createHttpPipeline code.

Likely just need one more line in createHttpPipeline code.

Reproduction

Any Builder class in clientcore test
https://github.com/microsoft/typespec/blob/main/packages/http-client-java/generator/http-client-generator-clientcore-test/src/main/java/type/array/ArrayClientBuilder.java

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• The provided reproduction is a minimal reproducible example of the bug.