[ios] bring back `channel` and `completed` params to showShareSheet() completion callback
[ios] bring back `channel` and `completed` params to showShareSheet() completion callback

BranchMetrics/react-native-branch-deep-linking,BranchMetrics/react-native-branch,BranchMetrics/react-native-branch,BranchMetrics/react-native-branch-deep-linking,BranchMetrics/react-native-branch-deep-linking,BranchMetrics/react-native-branch-deep-linking,BranchMetrics/react-native-branch,BranchMetrics/react-native-branch,BranchMetrics/react-native-branch,BranchMetrics/react-native-branch