ci: add xml reporting(experimental)

[obs-gh-nikhildua]

• Addresses https://observe.atlassian.net/browse/OB-37007

Why?

• We want better reporting for terraform tests in PRs. It's currently hard to see in CI what specific test failed in which job.
• This change makes it easier to see which test failed and the error the test surfaced without scrolling through logs.
• We use summary markdown from junit xml file to render the failure in summary screen
• We also change the naming convention for jobs to better identify things.

Other References:

Collapsing parallel github jobs (to make our CI tests less noisy in PR checks) is coming!
https://github.com/orgs/community/discussions/26246

See example:

Scrolling....

We can see exactly what test failed, where and the output logs without having to scroll through each job logs manually.

Another example showing that test_basic had failed