Fix SDL_TEXTINPUT ceased to dispatch for Desktop platforms on textinput focus.

[CoreTaxxe]

Fixes https://github.com/kivy/kivy/issues/8136

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• [ ] Title is descriptive/clear for inclusion in release notes.
• [ ] Applied a Component: xxx label.
• [ ] Applied the api-deprecation or api-break label.
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• [ ] Added to the milestone version it was merged into.
• [ ] Unittests are included in PR.
• [ ] Properly documented, including versionadded, versionchanged as needed.

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[CoreTaxxe]

Most of the line changes are just spacings and indents. The important code bits are config.py and kivy/core/window/_window_sdl2.pyx 628 +