test: run utils on Vitest

[cryptodev-2s]

Explanation

Moves @metamask/utils to Vitest.

References

• Part of the Jest to Vitest migration, see test: add Vitest alongside Jest #10546 for the shared setup

Checklist

• I've updated the test suite for new or updated code as appropriate
• I've updated documentation (JSDoc, Markdown, etc.) for new or updated code as appropriate
• I've communicated my changes to consumers by updating changelogs for packages I've changed
  • Not applicable, test only change. Carries the no-changelog label.
• I've introduced breaking changes in this PR and have prepared draft pull requests for clients and consumer packages to resolve them
  • None.

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Note

Low Risk
Test-only and tooling changes; no production runtime code in @metamask/utils is altered.

Overview
Migrates @metamask/utils from Jest + tstyche to Vitest for unit tests and built-in typecheck, consolidating test scripts and dropping Jest/tstyche config and dependencies.

Adds vitest.config.js (100% coverage thresholds, typecheck on) and removes jest.config.cjs. Test files switch to vi/vitest imports; mocks and spies are updated where Jest patterns do not carry over (@noble/hashes spy mocks, jest-when → explicit spy + toHaveBeenCalledWith, vi.stubGlobal for Error, proxy trap for isPlainObject, it.each %# for non-serializable fixtures). Former *.tst.ts type tests become *.test-d.ts using expectTypeOf (as const where literals matter).

Package tsconfig.json gains skipLibCheck so Vitest typecheck tolerates web3 declarations under exactOptionalPropertyTypes. @metamask/utils is removed from the repo Jest test-runner map; oxlint suppression entries are trimmed/renamed for the new file names.

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