docs: update useParams examples and pages usage

[paramoshkinandrew]

Updated https://nextjs.org/docs/app/api-reference/functions/use-params with:

• returns block, examples table: route with no dynamic parameters should return an empty object
• returns block, pages usage: if useParams is used in pages it will return null only for the initial render and will update its value with dynamic parameters following the same rules as stated in the doc above this point.

[ijjk]

Allow CI Workflow Run

• approve CI run for commit: 099e4d2

Note: this should only be enabled once the PR is ready to go and can only be enabled by a maintainer

[samcx]

Thank you for submitting a !