Add initSessionTtl to branch interface
Add initSessionTtl to branch interface

currently if `branch.initSessionTtl` is set typescript will throw an error
BranchMetrics/react-native-branch-deep-linking,BranchMetrics/react-native-branch-deep-linking,BranchMetrics/react-native-branch-deep-linking,BranchMetrics/react-native-branch-deep-linking