[Significant events][Streams] Zero shot copy update

[boriskirov]

Summary

This is a proposal to update the copy on the significant events tab in Streams to communicate that this is an onboarding task.

[macroscopeapp]

Approvability

Verdict: Needs human review

Simple UI copy and button styling changes with no runtime behavior impact. However, the file is owned by @elastic/obs-sig-events-team and the author is not a designated owner, so the owning team should review.

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[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 90e3ed78-1622-490b-82d6-6c412f436f80

📥 Commits

Reviewing files that changed from the base of the PR and between 14771a3 and 2d1cfd1.

📒 Files selected for processing (1)

• x-pack/platform/plugins/shared/streams_app/public/components/sig_events/stream_detail_significant_events_view/empty_state/index.tsx

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📝 Walkthrough

Walkthrough

The empty state UI in the significant events stream detail view was updated to represent an unonboarded stream state. The component's title message and description text were changed. The primary button label was updated from "Generate" to use a new localized string for "Onboard stream". Button styling was adjusted by replacing the fill property with a fixed medium size while preserving the existing loading/disabled states and generation/canceling label logic.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

• 🛠️ Update Documentation: Commit on current branch
• 🛠️ Update Documentation: Create PR

Warning

Tools execution failed with the following error:

Failed to run tools: 13 INTERNAL: Received RST_STREAM with code 2 (Internal server error)

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