Add missing e2e tests for different authentication methods

[shorim]

Description

For MetricPipeline and TracePipeline, there are 3 different authentication methods: Mutual TLS, Basic Authentication and Token-Based With Custom Headers as doumented here and here.

For LogPipeline, we have 2 different authentication methods: Mutual TLS and Basic Authentication as documented here.

Currently we have e2e tests for the 3 pipelines only for Mutual TLS authentication. We should also add e2e tests for the other authentication methods.

Reasons

Increase our e2e test coverage.

Criterias

• An e2e test for authentication using Basic Authentication is added for LogPipeline, MetricPipeline and TracePipeline.
• An e2e test for authentication using Token-Based With Custom Headers is added for MetricPipeline and TracePipeline.