Clean up beta notes and add link

[stefanjudis]

Affected Components

• Content & Marketing
• Pricing
• Test
• Docs
• Learn
• Other

Notes for the Reviewer

Very unspectecular; I've removed some dangling PWN beta notes and added a link. :)

[Copilot]

Pull Request Overview

This PR removes outdated beta-related notices from Playwright documentation and adds a helpful link to SLA documentation. The changes improve documentation accuracy by removing references to beta limitations that are no longer applicable and enhance usability by linking to related concepts.

Key changes:

• Removed beta runtime limits notice from Playwright Checks overview
• Removed beta warning from global configuration documentation
• Added link to SLA/SLO/SLI learning content

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
detect/synthetic-monitoring/playwright-checks/overview.mdx	Removed outdated beta runtime limits notice
detect/synthetic-monitoring/browser-checks/playwright-support.mdx	Removed beta warning from global configuration section
detect/synthetic-monitoring/playwright-checks/test-organization.mdx	Added link to SLA/SLO/SLI learning resource

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[stefanjudis]

I'll move forward to land the fixes and because I consider this to be uncritical. :)