Turbopack: keep side-effect-full imports (#76545)

This was already fixed by #77640 in the meantime

Adds a test for #76464

```js
// Inside a sideEffect: free module, ...

// ...imports without any bindings are completely dropped, even 
// if they reference modules which have `sideEffects: true`
import "./this-module-has-sideEffects";
```

Author: mischnic

Diff for: turbopack/crates/turbopack-tests/tests/execution/turbopack/side-effects-optimization/side-effect-import/input/index.js

@@ -0,0 +1,7 @@
+import { Parent } from './ui/src/index'
+
+it("should retain side effect-full imports", () => {
+  expect(Parent()).toBe("Parent Child")
+  expect(globalThis.sideEffectExecuted).toBe(true)
+});
+

Diff for: turbopack/crates/turbopack-tests/tests/execution/turbopack/side-effects-optimization/side-effect-import/input/ui/package.json

@@ -0,0 +1,5 @@
+{
+  "sideEffects": [
+    "./src/side-effect.js"
+  ]
+}

Diff for: turbopack/crates/turbopack-tests/tests/execution/turbopack/side-effects-optimization/side-effect-import/input/ui/src/Child.js

@@ -0,0 +1,6 @@
+import './side-effect.js'
+
+export function Child() {
+  return "Child"
+}
+export { Three } from './test'

Diff for: turbopack/crates/turbopack-tests/tests/execution/turbopack/side-effects-optimization/side-effect-import/input/ui/src/index.js

@@ -0,0 +1,5 @@
+import { Child } from './Child'
+
+export function Parent() {
+  return "Parent " + Child();
+}

Diff for: turbopack/crates/turbopack-tests/tests/execution/turbopack/side-effects-optimization/side-effect-import/input/ui/src/side-effect.js

@@ -0,0 +1 @@
+globalThis.sideEffectExecuted = true;

Diff for: turbopack/crates/turbopack-tests/tests/execution/turbopack/side-effects-optimization/side-effect-import/input/ui/src/test.js

@@ -0,0 +1 @@
+export const Three = 3

Diff for: turbopack/crates/turbopack-tests/tests/execution/turbopack/side-effects-optimization/side-effect-import/options.json

@@ -0,0 +1,3 @@
+{
+  "treeShakingMode": "reexports-only"
+}