Prevent empty or whitespace-only submissions with `Enter` key in textarea

[Anajrim01]

Issue Description

When pressing the Enter key in an empty or whitespace-only textarea, the form submits. This behavior needs to be modified so that pressing Enter in this state creates a new line instead.

Expected Behavior

• If the input is empty or contains only whitespace, pressing Enter should add a new line.
• If the input contains non-whitespace characters, pressing Enter should submit the form.

Steps to Reproduce

1. Focus on the textarea.
2. Press the Enter key when the textarea is empty or only contains whitespace.

Screenshots

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