Fix a typo in error message for non-text field validation

[uniquename]

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[Copilot]

Pull Request Overview

This PR fixes a grammatical error in an error message for field validation. The error message incorrectly stated "is must be" instead of "must be" when validating that a field is a text field.

Key Changes

• Corrected grammar in the error message by removing the redundant "is" from "is must be a text field"

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