fix: fix sharing of observation on Android 12+

[achou11]

Fixes #1097

Notes:

• Upgrades react-native-share to latest (8.2.2). Fix was introduced in 7.0.1.
• Slight uncertainty about the permissions change noted here: https://react-native-share.github.io/react-native-share/docs/migrate-v4-to-v5#removal-of-write_external_storage-permission-request. Not sure if it applies to us in this case (we're sharing file uris e.g. file:///data/user/0/com.mapeo.debug/files/media/preview/8a/8a6e62b150eae104f2cd59c78aac8948.jpg). from general testing, doesn't seem like the permission is needed to keep this working cc @gmaclennan
• Steps to verify fix (must use Android 12+ device):

1. Create observation that has an attachment (e.g. photo)
2. Open observation screen
3. Press Share button

[achou11]

~noticing that the preview isn't showing up in the share menu. can't remember if that's expected or not but guessing it's not because it shows up in the case where there's no attachments present.~

~seeing the same thing as https://github.com/react-native-share/react-native-share/issues/613 in adb logs - wondering if that's related. not really sure how to fix, but this doesn't seem to actually break the sharing itself, so hopefully not a major blocker for this PR~

UPDATE: this is not a regression as this is the previously observed behavior for observations without attachments, so please ignore this comment 😄

[achou11]

Closing in favor of #1099