[native] Bump react-native to 0.70.9

Summary: Just bumping react-native one patch version to include possible performance improvements described here: https://github.com/facebook/react-native/issues/36296. Thanks to @bartek for surfacing this issue.

Test Plan: yarn cleaninstall succeeded and things seem to work fine in iOS Simulator?

Reviewers: ashoat, ginsu, tomek, bartek

Reviewed By: ashoat

Subscribers: bartek

Differential Revision: https://phab.comm.dev/D9219