fix(orchestrator): prevent form submission on Enter in ActiveMultiSelect

[lokanandaprabhu]

Hey, I just made a Pull Request!

Fixes: https://issues.redhat.com/browse/RHDHBUGS-2506

Problem

When a user types a custom value in an ActiveMultiSelect widget (with ui:allowNewItems: true) and presses Enter, the Enter key event bubbles up to the form and triggers form submission, causing the form to advance to the next step.

Solution

• Added freeSolo prop to Autocomplete when allowNewItems is enabled, allowing custom values
• Added controlled inputValue with onInputChange handler for proper input state management
• Added onKeyDown handler that intercepts the Enter key when there's typed input:
  • Calls event.preventDefault() and event.stopPropagation() to prevent form submission
  • Adds the typed value as a new chip
  • Clears the input field

----------BEFORE-----------

Screen.Recording.2026-01-15.at.3.53.32.PM.mov

----------AFTER------------

Screen.Recording.2026-01-15.at.3.54.10.PM.mov

✔️ Checklist

• A changeset describing the change and affected packages. (more info)
• Added or Updated documentation
• Tests for new functionality and regression tests for bug fixes
• Screenshots attached (for UI changes)

[rhdh-gh-app]

Changed Packages

Package Name	Package Path	Changeset Bump	Current Version
@red-hat-developer-hub/backstage-plugin-orchestrator-form-widgets	workspaces/orchestrator/plugins/orchestrator-form-widgets	patch	v1.6.0

[sonarqubecloud]

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 SonarQube Cloud

[lokanandaprabhu]

/cc @mareklibra