fix(vitest): accept awaited return type in vi.when().thenResolve

[ErfanBagheri404]

Description

vi.when(spy).calledWith(...).thenResolve(value) currently requires value to be the full ReturnType, forcing callers to write Promise.resolve('bar') for async mocks. This changes thenResolve and thenResolveOnce to accept Awaited<ReturnType>, matching the existing mockResolvedValue / mockResolvedValueOnce signatures in @vitest/spy.

The runtime path already wraps the value in Promise.resolve(...) (when.ts case 'resolve'), so this is purely a type-level fix — no behavior change.

Before

vi.when(spy).calledWith('easter-egg').thenResolve(Promise.resolve('bar')) // required

After

vi.when(spy).calledWith('easter-egg').thenResolve('bar') // works

Related

Closes #11017

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