This reverts a fix to EditableText introduced in
https://github.com/matrix-org/matrix-react-sdk/pull/1445
which introduced a bug that causes room name and topic to
reset when UserSettings is rerendered because
`initialValue != this.value`
This also fixes the same bug originally fixed by #1445:
>fix entering the same thing twice (which had the bug of not
>emptying the "new" field)
which, in other words meant that clicking "+" when adding a room
alias would not reset the contents of the bottom-most alias in the
list.
The fix is to increment the `key` of the element, causing a new
instance to be mounted instead of passing new props to the existing
one.
016e9176f6