update contry & state translation migrations

[dimidev]

update migrate_data method at country & state migrations

[mrbrdo]

@dimidev not sure why you removed the null check, as I am getting null errors with proposed fix. I fixed the migrations in https://github.com/mrbrdo/spree_mobility/commit/3e19a0db1d86b212bd305af182d981f1e2a0fdcb