fix(ui): properly allows configuring rows for the textarea field

[PatrikKozak]

What?

Previously, setting the admin.rows property did not change the height of the textarea field input.

Why?

Although rows was being properly set on the textarea element - it's absolute positioning prevented the height from actually changing.

How?

Updates the styles of the textarea field component to properly allow the rows prop to change the height of the field.

Example w/:

{
  name: 'someTextArea',
  type: 'textarea',
  admin: {
    rows: 5,
  }
}

Before:

After:

Fixes #10017

[github-actions]

🚀 This is included in version v3.9.0