Stop in-source testing

I couldn't find out how to make `import.meta.vitest` `undefined` with
`@vercel/ncc`.

src/Aggregator.ts

@@ -15,10 +15,3 @@ export class Aggregator {
 		return this.source.fetch();
 	}
 }
-
-if (import.meta.vitest) {
-	const { it, expect } = import.meta.vitest;
-	it("true", () => {
-		expect(true).toBe(true);
-	});
-}

vitest.config.ts

@@ -1,10 +1,5 @@
 import { defineConfig } from "vitest/config";
 
 export default defineConfig({
-	test: {
-		includeSource: ["src/**/*.{js,ts}"],
-	},
-	define: {
-		"import.meta.vitest": "undefined",
-	},
+	test: {},
 });