bug: Missing navigation animations when navigating from tabs

# Bug Report
Navigating forward from a tab page to another sub-page will not show the router transition animation if the sub-page is listed inside the `tabs.router.module.ts`

**Ionic version:**

[x] **4.6**

**Current behavior:**

In my application I wanna show the tabs all the time also on sub pages. To react this case I have to list my subpages inside the `tabs.router.module.ts` file.
If I navigate now from Tab1 to Page1, there will be no router transition animation and the back button usage is not that intuitive anymore.

**Expected behavior:**

It should be possible to navigate from tabs to pages listed as subpages inside the `tabs.router.module.ts` file with router transition animations and back button support oob.

**Steps to reproduce:**

1. Create an new tabs project
2. Create a empty page
3. Add the page as a sub page inside the `tabs.router.module.ts` file
4. Navigate `forward` to the child page

**Related code:**
```ts
import { NgModule } from '@angular/core';
import { RouterModule, Routes } from '@angular/router';
import { TabsPage } from './tabs.page';

const routes: Routes = [
{
path: 'tabs',
component: TabsPage,
children: [
{
path: 'tabDatesRoot',
children: [
{
path: '',
loadChildren: '../pages/dates/dates.module#DatesPageModule'
}
]
},
{
path: '',
redirectTo: '/tabs/tabDatesRoot',
pathMatch: 'full'
},
{
path: 'pages',
children: [
{ path: 'map', loadChildren: '../pages/map/map.module#MapPageModule' },
]
}
]
},
{
path: '',
redirectTo: '/tabs/tabDatesRoot',
pathMatch: 'full'
}
];

@NgModule({
imports: [RouterModule.forChild(routes)],
exports: [RouterModule]
})
export class TabsPageRoutingModule {}
```

**Ionic info:**

```
Ionic:

Ionic CLI : 5.2.3 (/Users/danielsogl/.nvm/versions/node/v12.4.0/lib/node_modules/ionic)
Ionic Framework : @ionic/angular 4.6.2
@angular-devkit/build-angular : 0.13.9
@angular-devkit/schematics : 7.3.9
@angular/cli : 7.3.9
@ionic/angular-toolkit : 1.5.1

Capacitor:

Capacitor CLI : 1.1.1
@capacitor/core : 1.1.1

Utility:

cordova-res : not installed
native-run : not installed

System:

NodeJS : v12.4.0 (/Users/danielsogl/.nvm/versions/node/v12.4.0/bin/node)
npm : 6.10.1
OS : macOS Mojave```