Implement input method support to COSMIC-edit specific text widgets

[kenz-gelsoft]

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This is a FYI PR for future reference after the COSMIC team rebased the libcosmic to iced 14.0.

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 PRs I opened:

• Implement input method support to COSMIC specific text widgets libcosmic#1103

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

[kenz-gelsoft]

I rebase this PR onto iced-rebased branch in #539

closing