Starting IBus with no Input Methods overrides Keyboard Layout

## What Happened
Switchboard keyboard plug opened with one (non-US) keyboard layout and no Input Methods set.
Opened "Input method" tab and turned on IBus daemon

Later noticed that the keyboard layout being used was not the one set in the plug but the standard US one. (Will try and identify at what point this occurs).
The entry under the setting `org/gnome/desktop/input-sources/sources` showed only one keyboard layout - the non-US one that was set in the plug.
When an input method was set the correct keyboard layout started to be used again.

## Expected Behavior

Starting the IBus daemon with no input method should not override the selected keyboard layout.

## Steps to Reproduce

See above under "What Happened"

### Logs

## Platform Information
Elementary 6 daily