feat: ios handle custom activation rule

[achorein]

Summary

    "plugins": [
      [
        "expo-share-intent",
        {
              "iosActivationRules": "SUBQUERY (\nextensionItems,\n$extensionItem,\nSUBQUERY (\n$extensionItem.attachments,\n$attachment,\nANY $attachment.registeredTypeIdentifiers UTI-CONFORMS-TO \"com.adobe.pdf\"\n|| ANY $attachment.registeredTypeIdentifiers UTI-CONFORMS-TO \"public.file-url\"\n|| ANY $attachment.registeredTypeIdentifiers UTI-CONFORMS-TO \"public.url\"\n|| ANY $attachment.registeredTypeIdentifiers UTI-CONFORMS-TO \"public.jpeg\"\n|| ANY $attachment.registeredTypeIdentifiers UTI-CONFORMS-TO \"public.png\"\n).@count == $extensionItem.attachments.@count\n).@count >= 1",
         ...
        }
      ],

Todo

• Handle custom activation rule in plugin
• Map custom type identifier for pdf in ShareExtensionViewController
• Update README.md

Issue

Fixes #104