Always use job name for Terraform plan

What does this MR do?

This MR changes the Tfplan parser to always use job name for Terraform plan.

Closes #223563 (closed), #330838 (closed)

Screenshots

Result for pipeline:

plan:
  image: alpine:latest
  script:
    - echo '{"create":10,"update":5,"delete":8}' > report.json
  artifacts:
    name: tfplan-$WORKSPACE-$CI_JOB_ID
    reports:
      terraform: report.json
  parallel:
    matrix:
      - WORKSPACE: [workspace1, workspace2, workspace3]

Before	After

Does this MR meet the acceptance criteria?

Conformity

• I have included changelog trailers, or none are needed. (Does this MR need a changelog?)
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• I have self-reviewed this MR per code review guidelines.
• This MR does not harm performance, or I have asked a reviewer to help assess the performance impact. (Merge request performance guidelines)
• I have followed the style guides.
• This change is backwards compatible across updates, or this does not apply.

Availability and Testing

• I have added/updated tests following the Testing Guide, or it's not needed. (Consider all test levels. See the Test Planning Process.)
• I have tested this MR in all supported browsers, or it's not needed.
• I have informed the Infrastructure department of a default or new setting change per definition of done, or it's not needed.