Fixed rare "No such proxy method" error for native callback functions

Potential fix for IllegalStateException on Android

Fixed a native IllegalStateException (plugin still EOL)

Fixed share dialog not disappearing automatically when canceling a sh…

…are operation on iPhones (which could lead to share callback being called multiple times)

- Added AddEmailRecipient function (Android-only) (closed #140)

- Potential fix for rare "NSCallbackHelper is destroyed!" warnings
- Potential fix for #137

Added android:exported tag to NativeShareCustomDialogActivity for And…

…roid 12 support

Fixed seemingly harmless error message on Android: "java.lang.Securit…

…yException: Permission Denial: reading com.yasirkula.unity.NativeShareContentProvider uri ... requires the provider be exported, or grantUriPermission()"

Temporary bugfix for Android 12 devices (fixed #130)

Bugfix for a possible issue on Android 11 MIUI devices

Moved iOS build post-processor settings to 'Project Settings/yasirkul…

…a/Native Share'