Remove v0.24.0 deprecations

[ndonkoHenri]

Summary by Sourcery

This PR removes deprecated properties and enums that were marked for removal in version 0.27.0 of Flet. It also updates the Theme class to remove deprecated properties and references to ThemeVisualDensity, replacing them with VisualDensity.

Bug Fixes:

• Fixes an issue where enable_filter was incorrectly aliased to enable_search in the Dropdown control.

Enhancements:

• Updates the Theme class to remove deprecated properties and references to ThemeVisualDensity, replacing them with VisualDensity.

Chores:

• Removes deprecated image_src, image_src_base64, image_repeat, image_fit, and image_opacity properties from the Container control, advising users to use Container.image instead.
• Removes the deprecated disabled_color property from the CupertinoButton control, recommending the use of disabled_bgcolor instead.
• Removes the deprecated code_style property from the Markdown control, suggesting the use of code_style_sheet.code_text_style instead.