Remove extra decrement of transaction level

`rollback_active_record_state!` tries to restore model state on `Exception`
by invoking `restore_transaction_record_state` it decrement deep level by `1`.

After restoring state, `rollback_active_record_state!` ensure that states should be cleared
and level decremented by invoking `clear_transaction_record_state`,
which cause the bug: because state already reduced in `restore_transaction_record_state`.

Removed double derement of transaction level
and removed duplicated code which clear transaction state for top level.

Closes: #4566