test(ci): add pre-check system to CI workflow

[hardcoretime]

Description

Added pre-check system to CI workflow:

• Created script test/e2e/scripts/precheck-prepare_ci.sh that generates JSON report via ginkgo dry-run
• Integrated script call into .github/workflows/e2e-reusable-pipeline.yml
• Updated test/e2e/Taskfile.yaml to use FOCUS environment variable instead of hardcoded value
• Updated test/e2e/scripts/task_run_ci.sh to use $FOCUS variable

Why do we need it, and what problem does it solve?

Need the ability to prepare test information before running e2e tests in CI. The script performs ginkgo dry-run to generate a JSON report with test list that can be used for further analysis.

What is the expected result?

When CI pipeline runs precheck-prepare_ci.sh is executed, generating /tmp/e2e-specs.json.

Checklist

• The code is covered by unit tests.
• e2e tests passed.
• Documentation updated according to the changes.
• Changes were tested in the Kubernetes cluster manually.

Changelog entries

section: ci
type: chore
summary: "Add pre-check system to CI workflow for ginkgo dry-run preparation."