[Feature]: Custom handling for enter key in ComboboxInput

[abh1nash]

Describe the feature

By default, pressing enter on the ComboboxInput element triggers a click on the selected item. While this might be what is desired in a lot of cases, its not ideal because:

1. it removes any native event data - the event comes through as a click event even when user pressed enter
2. in some cases, such as a search box with suggestions, this is not ideal as the enter key should trigger a search with user's query instead of selecting the first result of the suggestion

To alleviate this, inputEnterFunction could be provided to the ComboboxRoot element, which will perform custom action on pressing enter.

Additional information

• I intend to submit a PR for this feature.
• I have already implemented and/or tested this feature.