fix(`@vtmn/css`): fix padding end with child count for `VtmnSearch`

[Tlahey]

Changes description

Closes #1434

Meet with @thibault-mahe Choice made, applied a background-color primary behind the buttons. Challenge with the designers if a disable state is necessary on a search component. ⚠️ Disabled will not changed the background-color behind the inputs, but as I said, we have to challenge.

Context

With the current search css, the placeholder doesn't takes all the input

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

[lauthieb]

Thank you @Tlahey