Fix Issue #223

[teamomiamigo]

Fixes Issue #223: Integrate color picker for apptheme option in settings (more page)

this PR works on customizing the app's theme color.
CHANGES:
themeprovider

• added an updateThemeColor function to dynamically update and persist the app's theme color
  AppeThemeSelectorScreen
• removed the react-native-color picker that also relied on the Slider API and replaced it with react-native-color-wheel
• updated modal logic to display color wheel and confirm color selection
• maintained existing UI elements (+ button, predefined theme swatches)

WHY:

• previous library used a removed slider and react native core, causing runtime errors
• enhancing theme customization to improve the user personalization
• react-native-color-wheel tries to avoid any dependency issue, and might provide a cleaner solution but needs to be checked if it will still work in relation to the dependency issues that are still there.