chore: enable noUncheckedSideEffectImports TypeScript option (#861)

This change should have no user impact.

[`noUncheckedSideEffectImports`][0] checks side-effect imports, such as:

```typescript
// Not actually importing anything from this module.
import 'example'
```

This enables that option.

No code changes were required; it may help avoid future mistakes.

[0]: https://www.typescriptlang.org/tsconfig/#noUncheckedSideEffectImports

tsconfig.json

@@ -4,6 +4,7 @@
     "lib": ["es2022"],
     "noImplicitAny": true,
     "noImplicitThis": true,
+    "noUncheckedSideEffectImports": true,
     "strictNullChecks": true,
     "strictBindCallApply": true,
     "strictFunctionTypes": true,