caretPosition: Delete pointless logic in `getPosition()`
caretPosition: Delete pointless logic in `getPosition()`

The `line` variable is unconditionally overwritten later, and the
function calls do not have side effects, so it is safe to delete this
logic.

ether/etherpad-lite,ether/etherpad-lite,storytouch/etherpad-lite,storytouch/etherpad-lite,storytouch/etherpad-lite,ether/etherpad-lite