Messenger z-index issues

Summary

Two errors:

1. form toasts container occludes the conversation's text input
2. the sidebar appears on top of the messenger:

Steps to reproduce

1. Open the window in a ~1350px wide resolution, open only one messenger conversation and click on the text input.
2. Open the window in a really narrow resolution with the conversation opened.

What is the current bug behavior?

1. Cannot type into the text input because the form toast spacer is occluding it.
2. the conversation appears behind the messenger

Possible fixes

1. Only render the form toast container if there's visible toasts
2. fix z-index