Implement input method support to COSMIC-edit specific text widgets (for iced-rebase branch)

[kenz-gelsoft]

The input method support in iced 14.0 requires text widgets to implement some logic to support input method input. This PR includes this for the cosmic-edit specific text widgets.

This PR depends on my pop-os/libcosmic fork. Please see PR I opened:

• Implement input method support to COSMIC specific text widgets libcosmic#1142

(I will force-push this branch to update my fork to rebase to newer upstream rev)

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