Make more-licenses.md deterministic by removing generated timestamp noise

[Copilot]

Context

Merging PRs such as #4781 causes other pending PRs to almost certainly have a conflict in

• more-licenses.md's 4th line, which is an auto-generated timestamp, for example: Bump com.github.jk1.dependency-license-report from 3.1.2 to 3.1.4 #4746, Bump com.github.oshi:oshi-core from 7.2.1 to 7.4.2 #4743 and Bump the opentelemetry group across 1 directory with 8 updates #4767.
• potentially 20 or more auto-generated gradle.lockfiles where changed versions are neighbors, for example: Bump the opentelemetry group across 1 directory with 8 updates #4767.

Copilot

licenses/more-licenses.md was non-deterministic because generateLicenseReport injected a per-run timestamp, creating guaranteed merge conflicts across concurrent dependency PRs with no semantic content differences. This change removes that source of churn and simplifies the PR-helper logic that previously special-cased it.

• Deterministic license report output

  • Added a generateLicenseReport post-processing step in agent/agent/build.gradle.kts that removes only the timestamp line matching _YYYY-MM-DD HH:MM:SS UTC_ immediately after ## Dependency License Report.
  • Match is pattern-based (not line-number-based) and idempotent.

• Workflow cleanup

  • Simplified .github/workflows/pull-request-helper.yml (“Update license report” step) by removing the --shortstat timestamp heuristic.
  • Uses the standard staged-diff check already used elsewhere in the workflow:
    • generate report
    • git add licenses
    • git diff --cached --quiet → no-op if unchanged, commit otherwise

• Regenerated committed artifact

  • Updated licenses/more-licenses.md to reflect deterministic output (timestamp line removed, dependency/license content unchanged).

named("generateLicenseReport").configure {
  doLast {
    val normalized = reportContents.replace(
      Regex("""(?m)(^## Dependency License Report\r?\n)_\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2} UTC_\r?\n"""),
      "$1",
    )
  }
}