[chat] send message widget broken after sending multiline messages

The text-edit widget has the tendency to keep its expanded height after containing multiline content.

• OS: all
• Jami version: master
• What build you are using: build

Steps to reproduce

• Can you reproduce the bug: at will
• Steps:

1. open a conversation
2. make sure text editing mode is off and create a multiline message, then send it

• Actual result: the text edit widget doesn't collapse to it's original height

• Expected result: the text edit widget should return to a single line

Additional information

Engaging in text-edit mode afterward will cause more elaborate UI issues:

This will be accompanied by: qrc:/mainview/components/ChatViewFooter.qml:103:5: QML ColumnLayout: Layout polish loop detected for QQuickColumnLayout(0x575db88a4220, parent=0x575db87d89e0, geometry=0,0 490x56). Aborting after two iterations.