feat: Un-deprecate plugin and make it Capacitor v4 compatible

[piotr-cz]

Is your feature request related to a problem? Please describe:
As stated in readme, Capacitor v4 supports dark mode on Android - however it doesn't work for WebView versions lower than ~ v100.
At the same time, Capacitor v4 supports Android WebView 60+

Describe the solution you'd like:

• Un-depreacate plugin
• Add Capacitor v4 compatibility (constant has changed in androidx.webkit 1.3)

  src/main/java/dev/robingenz/capacitor/androiddarkmodesupport.java
   if (WebViewFeature.isFeatureSupported(WebViewFeature.FORCE_DARK_STRATEGY)) {
  -    WebSettingsCompat.setForceDarkStrategy(settings, WebSettingsCompat.WEB_THEME_DARKENING_ONLY);
  +    WebSettingsCompat.setForceDarkStrategy(settings, WebSettingsCompat.DARK_STRATEGY_WEB_THEME_DARKENING_ONLY);
   }

• Add note that plugin is required for older WebView versions

Describe alternatives you've considered:
I've tried @aparajita/capacitor-dark-mode however it's not a straight forward drop-in solution as this plugin is

Additional context:
Some of related issues:

• Plugin to enable prefers-color-scheme on all platforms by enabling it in android ionic-team/capacitor-plugins#1010
• bug: 🌙 Dark mode not detected in JavaScript and CSS  ionic-team/capacitor#4677