Add JumpCloud name casing exception to SIEM-Names

[gfoss]

Summary

• Adds JumpCloud as a sentence-case exception to allow correct brand casing in detection rule names (e.g., "Multiple JumpCloud push notifications denied", "Credential stuffing attack on JumpCloud")

This follows the same pattern as existing entries like Jamf Protect and Okta.

Test plan

• Vale linter passes on updated JumpCloud detection rule names in security-monitoring

🤖 Generated with Claude Code

[domalessi]

Thanks for the update!