fix(sentence-case): add 'Creating backup…'

[david-allison]

Note

Assisted-by: Assisted-by: Claude Fable 5.1

Purpose / Description

Handle the sentence cased backend via fixing the ellipsis.

Fixes

• Fixes [Design] Inconsistent String Casing #15760 🚀

Approach

Special-case rewriting ... to …

How Has This Been Tested?

Unit tested

Checklist

• You have a descriptive commit message with a short title (first line, max 50 chars).
• You have commented your code, particularly in hard-to-understand areas
• You have performed a self-review of your own code
• UI changes: include screenshots of all affected screens (in particular showing any new or changed strings)
• UI Changes: You have tested your change using the Google Accessibility Scanner

[github-actions]

Snapshot diff report vs main. Open screenshot-diff for diffs.

• TemplatePreviewerScreenshotTest: 1 change

All 1 changed screenshots

TemplatePreviewerScreenshotTest

• base_compare.png