Introduce FluentNotificationTriggerModel for FluentNotifcation to rework the Bump animation

[nodes11]

Platforms Impacted

• iOS
• visionOS
• macOS

Description of changes

This change introduces the FluentNotificationTriggerModel, which simplifies client interactions with FluentNotification. Currently, most of the notification state is managed through MSFNotificationStateImpl, but this is not publicly exposed on the notification. Instead of exposing the MSFNotificationStateImpl property on the notification, we are introducing a new observable model that clients can easily interact with.

The first use case for this new model is to expose the bump behavior. Previously, this behavior was enabled through the state object. However, pure SwiftUI views did not have a straightforward way to trigger it. With this change, clients can now set triggerModel.shouldBump = true, and the notification view will respond accordingly.

This change also adds an option onDismiss parameter to the FluentNotification init which will be passed along to the state property. This is purely for the convienece of apps that use FluentNotification directly.

Binary change

(how is our binary size impacted -- see https://github.com/microsoft/fluentui-apple/wiki/Size-Comparison)

Verification

Validated in internal use cases. Updated demo controllers. See demo videos below.

Visual Verification

Simulator.Screen.Recording.-.iPhone.17.Pro.-.2026-02-20.at.12.01.35.mov

Simulator.Screen.Recording.-.iPhone.17.Pro.-.2026-02-20.at.12.16.20.mov

Pull request checklist

This PR has considered:

• Light and Dark appearances
• iOS supported versions (all major versions greater than or equal current target deployment version)
• VoiceOver and Keyboard Accessibility
• Internationalization and Right to Left layouts
• Different resolutions (1x, 2x, 3x)
• Size classes and window sizes (iPhone vs iPad, notched devices, multitasking, different window sizes, etc)
• iPad Pointer interaction
• SwiftUI consumption (validation or new demo scenarios needed)
• Objective-C exposure (provide it only if needed)

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