bug: missing state property on routerLink

# Bug Report

**Ionic version:**

[x] **4.x**

**Current behavior:**

state is being ignored.

**Expected behavior:**

state must be set.

**Steps to reproduce:**

**Related code:**
https://angular.io/api/router/RouterLink
page.html
```
...

This doesn't work

...
This works
```

childPage.ts
```
...
constructor(private userDao: UsersDao, private activatedRoute: ActivatedRoute, private router: Router) {}

async ngOnInit() {
this.activatedRoute.params.subscribe(async params => {
const state = this.router.getCurrentNavigation().extras.state;
console.log({ state: this.router.getCurrentNavigation().extras });
if (state && state.user) {
console.log("State found");
this.user = state.user;
} else {
console.log("State not found");
const id = params.id;
this.user = await this.userDao.get(id);
}
});
...
```

NavController supports it:
this.navCtrl.navigateForward([`/users/${user.id}`], { state: { user } });

**Other information:**

**Ionic info:**

Start with the routerLink handling for ion-item and compare it with the working anchor example in page.html; the issue links Angular's RouterLink documentation and shows the childPage.ts navigation-state lookup. Reproduce the case with [state] on ion-item, then verify that the user state is available through getCurrentNavigation().extras.state as it is for the anchor and NavController examples.

由索引模型根据 Issue 内容生成。