Fixed minor typo in sample of BluetoothLEHelper.md

[szv]

What changes to the docs does this PR provide?

Fixes a minor typo if your choice to of your choice.

PR Checklist

Please check if your PR fulfills the following requirements:

• [x] Correctly picked the right branch to base the change off (dev for new features, main for typos/improvements)
• [x] For new pages, used the provided template
• [x] For new features, added an entry in the Table of Contents
• [x] Ran against a spell and grammar checker
• [x] Contains NO breaking changes

[learn-build-service-prod[bot]]

Learn Build status updates of commit d63ad60:

:white_check_mark: Validation status: passed

File	Status	Preview URL	Details
docs/helpers/BluetoothLEHelper.md	:white_check_mark:Succeeded	View

For more details, please refer to the build report.

For any questions, please:

• Try searching the learn.microsoft.com contributor guides
• Post your question in the Learn support channel