Position of Members list should not flow out of page. applicable to both width and height

[abhikanojia]

Steps to Replicate:

• Add the textarea to right most side of page. try to mention member.
• the list that is populated will add scroll to the existing page.

[fritx]

@abhikanojia yes, it would be nice to fix the bug

Related issues: https://github.com/fritx/vue-at/issues/5, https://github.com/fritx/vue-at/issues/56

[jhlee8804]

+1