fix(sandbox-local): block-body the default rmTempDir fallback

The arrow shorthand implicitly returns rmSync's void, which the
no-confusing-void-expression rule forbids; the block body keeps the
fallback without the violation.

packages/sandbox/sandbox-local/src/index.ts

@@ -481,7 +481,7 @@ export class LocalSandboxProvider extends SandboxProvider {
         failures.push(error)
       }
     }
-    const rmTempDir = this.internals.rmTempDir ?? ((dir: string) => rmSync(dir, { recursive: true, force: true }))
+    const rmTempDir = this.internals.rmTempDir ?? ((dir: string) => { rmSync(dir, { recursive: true, force: true }) })
     for (const dir of this.tempDirs.values()) {
       try {
         rmTempDir(dir)