fix(@vtmn/react): add missing onChange event to `VtmnDropdown`

[0x2A-git]

Changes description

Injected new event in VtmnDropdown's children and then called children's callback. This event was missing according to the showcase : https://www.decathlon.design/726f8c765/v/0/p/42d824-dropdown/b/28931f

Context

This P.R aims to resolve issue #1377 by adding an onChange event to VtmnDropdown component.

Checklist

• [X] Make sure you are requesting to pull a topic/feature/bugfix branch. Please, don't request directly from your main!
• [X] Check commits & PR names matches our requested structure. It must follow the https://www.conventionalcommits.org pattern.
• [X] Check your code additions will fail neither code linting checks.
• [X] I have reviewed the submitted code.
• [X] I have tested on related showcases.
• [X] If it includes design changes, please ask for a review design-system-core-team-design GitHub team.

Does this introduce a breaking change?

• No

Other information

[0x2A-git]

Thanks! Now that's ok for me. @Decathlon/design-system-core-contrib-web-dev can you please review?

Nice ! Thanks for having pointed out this issue I didn't notice it when testing it :S

Good afternoon :D