chore: use with instead of assert in rollup.mjs

[negezor]

Fixes a build error on newer versions of Node.js. Import attributes by specification should use with keyword instead of assert and it's already on stage 3, so proposal is accepted. https://github.com/tc39/proposal-import-attributes

This is also mentioned in TypeScript 5.3 https://devblogs.microsoft.com/typescript/announcing-typescript-5-3/#import-attributes

Scope: 3 of 4 workspace projects
packages/router build$ rimraf dist && rollup -c rollup.config.mjs
│ [!] SyntaxError: Unexpected identifier 'assert'

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 97.32%. Comparing base (7422b15) to head (4006a6c).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2326   +/-   ##
=======================================
  Coverage   97.32%   97.32%           
=======================================
  Files          26       26           
  Lines        6013     6013           
  Branches      819      819           
=======================================
  Hits         5852     5852           
  Misses        159      159           
  Partials        2        2           

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[posva]

Thanks!