Textarea component loses borders under certain conditions

[brandongregoryscott]

Similar to #1581, after https://github.com/segmentio/evergreen/releases/tag/v7.1.0 we noticed the Textarea component can lose its borders in certain conditions. One way to reproduce is:

1. Open https://evergreen-storybook.netlify.app/?path=/story/file-uploader--fileuploader
2. Click the Textarea story

Note that just opening https://evergreen-storybook.netlify.app/?path=/story/textarea--overview or hard-refreshing solves the issue. We should remove the border: none that's also in its internal styles...

evergreen/src/textarea/src/Textarea.js

Lines 16 to 17 in 3c6184d

	const internalStyles = {
	border: 'none',