bug(Overlay): FlexibleConnectedPositionStrategy withViewportMargin not working

### Is this a regression?

- [ ] Yes, this behavior used to work in the previous version

### The previous version in which this bug was not present was

_No response_

### Description

When using overlay with `FlexibleConnectedPositionStrategy` and `withViewportMargin()`, overlay ignores provided margin value and still opens in first preffered position, when it should move to second one. Overlay cant be pushed and has no flexible dimmensions set.

### Reproduction

https://stackblitz.com/edit/viewport-margin-bug?file=src%2Fapp%2Fapp.component.ts
(Red line shows 100px margin edge)

Steps to reproduce:
1. Create overlay with popup 100px x 100px
2. Locate its origin point 150px from top edge of viewport.
3. Add two positions to FlexibleConnectedPositionStrategy:
```
{
originX: 'end',
originY: 'top',
overlayX: 'start',
overlayY: 'bottom',
},
{
originX: 'end',
originY: 'bottom',
overlayX: 'start',
overlayY: 'top',
},
```
4. Use `withViewportMargin(100)`.
5. Use `withFlexibleDimensions(false)`
6. Use `withPush(false)`

### Expected Behavior

Since `withViewPortMargin(100)` was set, and overlay cannot be pushed or shrinked, then it should fallback to second preffered position in which popup opens downwards.
```
{
originX: 'end',
originY: 'bottom',
overlayX: 'start',
overlayY: 'top',
},
```

### Actual Behavior

Overlay still opens according to first position which is upward, ignoring viewport margin

### Environment

- Angular: 13.1.3
- CDK/Material: 13.1.3
- Browser(s): Chrome 97
- Operating System (e.g. Windows, macOS, Ubuntu): macOS

Beginne mit der verlinkten StackBlitz-Reproduktion und untersuche FlexibleConnectedPositionStrategy. Konzentriere dich dabei darauf, wie withViewportMargin mit deaktivierten flexiblen Dimensionen und dem Push-Verhalten interagiert. Die Aufgabe ist abgeschlossen, wenn das Overlay auf die zweite Position zurückfällt, sobald die erste den 100px-Viewport-Rand verletzt, und eine Testabdeckung für die gemeldete Konfiguration vorhanden ist.

Vom Indexierungsmodell aus dem Issue-Text verfasst.