Fix typo incorrect article before "user interface"

[alexchrysovergis]

What?

Closes #69167

Why?

The phrase "an user interface" is grammatically incorrect because "user" starts with a consonant sound, which requires the article "a" instead of "an". This small fix improves the clarity of the documentation.

How?

Updated the documentation by replacing "an user interface" with "a user interface".

Testing Instructions

Review the updated documentation text.
Confirm that the grammar is now correct.

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[github-actions]

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[fabiankaegy]

good catch :)