fix(useSearchParam): fix difference client server

[RomainGaillard33]

Description

Fix difference client / server on useSearchParam hook.

On SSR useSearchParam return null (it's normal). But on client side, useSearchParam, return directly value. It's not good. This causes a client/server difference. You must return the value on the client side, only after a "did mount".

Type of change

• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as before)

Checklist

• [ ] Read the Contributing Guide
• [x] Perform a code self-review
• [ ] Comment the code, particularly in hard-to-understand areas
• [ ] Add documentation
• [ ] Add hook's story at Storybook
• [ ] Cover changes with tests
• [ ] Ensure the test suite passes (yarn test)
• [ ] Provide 100% tests coverage
• [x] Make sure code lints (yarn lint). Fix it with yarn lint:fix in case of failure.
• [x] Make sure types are fine (yarn lint:types).