fix(core/modal): fires 2 events on closing

[matthiashader]

💡 What is the current behavior?

• modal closing fires 2 events

GitHub Issue Number: Closes #1149, [IX-985]

🆕 What is the new behavior?

• removed onClose / onDismiss on dialog as this triggers the closing methods again

🏁 Checklist

A pull request can only be merged if all of these conditions are met (where applicable):

• 🦮 Accessibility (a11y) features were implemented
• 🗺️ Internationalization (i18n) - no hard coded strings
• 📲 Responsiveness - components handle viewport changes and content overflow gracefully
• 📄 Documentation was reviewed/updated (pnpm run docs)
• 🧪 Unit tests were added/updated and pass (pnpm test)
• 📸 Visual regression tests were added/updated and pass (Guide)
• 🧐 Static code analysis passes (pnpm lint)
• 🏗️ Successful compilation (pnpm build, changes pushed)

👨‍💻 Help & support

[changeset-bot]

🦋 Changeset detected

Latest commit: 2ef227f

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

This PR includes changesets to release 4 packages

Name	Type
@siemens/ix	Patch
@siemens/ix-angular	Patch
@siemens/ix-react	Patch
@siemens/ix-vue	Patch

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[sonarcloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

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

See analysis details on SonarCloud