Update Terraform/Base.latest.gitlab-ci.yml to inline cd TF_ROOT

What does this MR do?

At present this template appears to be designed to never interfere with other jobs in your CI YML. This is true for all cases except the global before_script which will cause other jobs in your .gitlab-ci.yml to possibly end up in the wrong directory. This was specifically important for a use case where a project was using terraform and ansible in https://gitlab.com/gitlab-org/quality/gitlab-environment-toolkit . The simplest solution appears to be to just inline the cd ${TF_ROOT}. We also considered defining another hidden job that is extended by all the other jobs here but the indirection didn't seem worth it for a single step.

Screenshots (strongly suggested)

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• [-] Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team