fix(Vehicle Maintenance Schedule): Changes in Maintenance Sheet and Schedule

[Mariyaaahh]

Current System: If a vehicle misses a scheduled maintenance, it will not appear in the Vehicle Maintenance Schedule until the previous maintenance has been done.

For example: If 5k is due and the customer misses that maintenance then the system will not remind the user for the 10k maintenance.

The user wants to ensure that even if a customer misses paying 5k, their name will still appear in the 10k maintenance schedule report.

Solution: for now, if a customer misses the 5k, the system checks the last one, the third free service, and after 6 months, it'll shows the maintenance of 10k.