The Enter link dialog is displayed incorrectly

[vidasaskinis]

When adding a link and scrolling down the "Enter link" dialog is displayed over other content.

Steps for Reproduction

1. Visit [(https://quilljs.com/playground/form)]
2. Add more text to the text area so that a vertical scroll would appear
3. Choose some text at the top and click "link" button
4. "Enter link" dialog appears
5. Scroll to the bottom of the text area

Expected behavior:
"Enter link" dialog is not covering content outside the text area
Actual behavior:
"Enter link" dialog is hiding content outside the text area

Version: 2.0.3

P.S. I know that some z-index would probably solve this but in my opinion this should not happen by default and user should not be made to change .ql-link or other styles.