fix(LVGLImage): use lv_image_dsc_t instead of lv_img_dsc_t

[PierreRambaud]

Description of the feature or fix

The lv_img_dsc_t is deprecated and should be replaced by lv_image_dsc_t

Notes

• Update the Documentation if needed.
• Add Examples if relevant.
• Add Tests if applicable.
• If you added new options to lv_conf_template.h run lv_conf_internal_gen.py and update Kconfig.
• Run scripts/code-format.py (astyle needs to be installed) and follow the Code Conventions
• Mark the Pull request as Draft while you are working on the first version, and mark is as Ready when it's ready for review.
• When changes were requested, re-request review to notify the maintainers.
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[XuNeo]

Thank you!