fix(@vtmn/svelte, @vtmn/react, @vtmn/vue): fix rounded value on `VtmnRating`

[Tlahey]

Changes description

After checking the Decathlon website, I saw many products that the stars are stuck at 4.5.

But some of them are a rating > 4.7.

Context

The rule on the current component is :

• If my value are a floating value, always round on the 0.5 above.

But here with a value > 4.5 we don't round.

The question here is, what we defined when a number is > 4.5. I've discuss with @lauthieb, we need to speak about it, maybe take the example of Google that round the value with the nearest one.

And write this rule on the Design System website so that there are no more questions about it.

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 breaking changes

Other information

This PR aims to enhancer the storybook

• Add conditional values in order to display only specific fields when readonly are true / false

Readonly = false	Readonly = true

Improve tests

• Move the function who compute the VtmnIcon who has to be displayed. Add more tests on this function.
• Add more test on the component

[lauthieb]

Hi @Tlahey, Thanks for your PR, I just proposed you a meeting when you will be back to work next Monday to discuss about this. See you soon. Laurent

[lauthieb]

Thanks @Tlahey, that's ok for me! I also added it this fix for React & Vue implementation of the VtmnRating component.