[FEATURE] Improve test coverage for MLHttpClientFactory.java

[dhrubo-os]

We need to improve test coverage in our repo.

This issue will target only to improve test coverage for MLHttpClientFactory.java class

From this url we can see where test coverage is missing for this class: https://app.codecov.io/gh/opensearch-project/ml-commons/blob/2.x/ml-algorithms%2Fsrc%2Fmain%2Fjava%2Forg%2Fopensearch%2Fml%2Fengine%2Fhttpclient%2FMLHttpClientFactory.java

[Arnav-Gr0ver]

@dhrubo-os Hello Dhrubo! I would like to take up this feature as my first issue

[dhrubo-os]

Sure.

[dhrubo-os]

@Arnav-Gr0ver any update on this?

[akolarkunnu]

@dhrubo-os Can you please assign this to me, I will work on this.

[dhrubo-os]

Sure, thanks for looking into this.