feat(apps): improve ErrorMessage type safety

[taymoor89]

Summary

Improve ErrorMessage component to accept unknown error types, eliminating unsafe type casting.

Changes Made

• Change error prop type from Error to unknown
• Remove unsafe type casting at 4 places.
• Add proper type guards for Error, string, and unknown types
• Simplify string error handling

Related Issues

• Fixes [Task](juno): Improve ErrorBoundary types #1431

Testing Instructions

1. pnpm i
2. pnpm test ErrorMessage
3. pnpm typecheck

Checklist

• I have performed a self-review of my code.
• I have commented my code, particularly in hard-to-understand areas.
• I have added tests that prove my fix is effective or that my feature works.
• New and existing unit tests pass locally with my changes.
• I have made corresponding changes to the documentation (if applicable).
• My changes generate no new warnings or errors.
• I have created a changeset for my changes.

[changeset-bot]

🦋 Changeset detected

Latest commit: 0a98037

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 2 packages

Name	Type
@cloudoperators/juno-app-greenhouse	Patch
@cloudoperators/juno-app-heureka	Patch

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[Copilot]

Pull request overview

Updates the ErrorMessage component (in both Heureka and Greenhouse apps) to accept unknown errors and safely derive a displayable name/message without as Error casts, aligning with react-error-boundary’s unknown-typed errors.

Changes:

• Widen ErrorMessage’s error prop from Error to unknown and add type-guarded formatting (Error, string, fallback).
• Remove unsafe casts at call sites and pass through unknown errors directly.
• Add unit tests covering string and non-Error unknown error inputs.

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
apps/heureka/src/components/common/getErrorDataRow.tsx	Removes as Error cast; passes unknown error into ErrorMessage.
apps/heureka/src/components/common/Filters/index.tsx	Removes as Error cast when forwarding react-error-boundary error.
apps/heureka/src/components/common/Filters/PlaceHolderFilterSelect.tsx	Widens error prop to unknown and changes how errortext is derived.
apps/heureka/src/components/common/ErrorBoundary/ErrorMessage.tsx	Adds unknown-safe error normalization and updates rendering.
apps/heureka/src/components/common/ErrorBoundary/ErrorMessage.test.tsx	Adds tests for string and unknown-object errors.
apps/greenhouse/src/components/admin/common/getErrorDataRow.tsx	Removes as Error cast; passes unknown error into ErrorMessage.
apps/greenhouse/src/components/admin/common/YamlViewer.tsx	Passes string error directly into ErrorMessage instead of wrapping in Error.
apps/greenhouse/src/components/admin/common/ErrorBoundary/ErrorMessage.tsx	Adds unknown-safe error normalization and updates rendering.
apps/greenhouse/src/components/admin/common/ErrorBoundary/ErrorMessage.test.tsx	Adds tests for string and unknown-object errors.
.changeset/improve-error-message-type-safety.md	Records patch release for both apps.

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