DataGrid tabbing doesnt bring the next cell fully into view, when space allows

[Xiaoy312]

Describe the bug

When moving to the next cell using Tab, the cell is not fully scrolled-into-view nor has one of its edges snapped to the DataGrid's viewport.

Regression

No response

Reproducible in sample app?

• This bug can be reproduced in the sample app.

Steps to reproduce

[u14311.zip](https://github.com/CommunityToolkit/WindowsCommunityToolkit/files/15080942/u14311.zip)

1. launch u14311.Windows
2. resize the app window until roughly only 2 rows can be displayed
3. select R1C1 first cell from first row
4. spam <kbd>Tab</kbd>

Expected behavior

The cell should be fully visible, or have one of its edge snapped to the data-grid's viewport.

Screenshots

Windows Build Number

• Windows 10 1809 (Build 17763)
• Windows 10 1903 (Build 18362)
• Windows 10 1909 (Build 18363)
• Windows 10 2004 (Build 19041)
• Windows 10 20H2 (Build 19042)
• Windows 10 21H1 (Build 19043)
• Windows 11 21H2 (Build 22000)
• Other (specify)

Other Windows Build number

No response

App minimum and target SDK version

• Windows 10, version 1809 (Build 17763)
• Windows 10, version 1903 (Build 18362)
• Windows 10, version 1909 (Build 18363)
• Windows 10, version 2004 (Build 19041)
• Other (specify)

Other SDK version

No response

Visual Studio Version

2022

Visual Studio Build Number

No response

Device form factor

No response

Nuget packages

CommunityToolkit.WinUI.UI.Controls@7.1.2

Additional context

In repro for this problem to manifest, the cell's should have a significant difference in size between its normal and edit mode.

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