test: remove esbuild config for vitest

[MikeMcC399]

Situation

corepack yarn test outputs the warning similar to the following:

Both esbuild and oxc options were set. oxc options will be used and esbuild options will be ignored. The following esbuild options were set: { target: 'node24.14.1' }

corepack/vitest.config.mts

Lines 10 to 12 in 05bc5f3

	esbuild: {
	target: `node${process.versions.node}`,
	},

Change

In vitest.config.mts remove the conflicting esbuild.target

This is being ignored and oxc automatically targets the current Node.js version, which is also the intention of the esbuild key.