ACM-24278 Implemented common cluster namespaces generation logic

[mshort55]

📝 Summary

This implements the common namespaces logic. It gets all namespaces from all managed clusters through search one time and creates a map to be used when cluster selection changes.

Ticket Summary (Title):
RBAC UI Implementation - Common namespaces drop down in RA creation

Ticket Link:
https://issues.redhat.com/browse/ACM-24278

Type of Change:

• 🐞 Bug Fix
• ✨ Feature
• 🔧 Refactor
• 💸 Tech Debt
• 🧪 Test-related
• 📄 Docs

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✅ Checklist

General

• PR title follows the convention (e.g. ACM-12340 Fix bug with...)
• Code builds and runs locally without errors
• No console logs, commented-out code, or unnecessary files
• All commits are meaningful and well-labeled
• All new display strings are externalized for localization (English only)
• (Nice to have) JSDoc comments added for new functions and interfaces

If Feature

• UI/UX reviewed (if applicable)
• All acceptance criteria met
• Unit test coverage added or updated
• Relevant documentation or comments included

If Bugfix

• Root cause and fix summary are documented in the ticket (for future reference / errata)
• Fix tested thoroughly and resolves the issue
• Test(s) added to prevent regression

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🗒️ Notes for Reviewers

[mshort55]

/assign @oksanabaza @kurwang

[mshort55]

/hold

[mshort55]

/unhold

[oksanabaza]

/lgtm

[openshift-ci]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: mshort55, oksanabaza

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• frontend/src/routes/UserManagement/OWNERS [mshort55,oksanabaza]

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
96.2% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud