Missing MultiCastPingSlotPeriod parameter for Class B device in fuota_server.go

[heidimao]

We ran into an this bug when testing fuota deployment with Class B device:
pingNB must be > 0

The possible reason is that the MultiCastPingSlotPeriod parameter is missing in fuota_server.go
https://github1s.com/brocaar/chirpstack-fuota-server/blob/e049e20ec9711fdc6900dc569f2ccd57496bd466/internal/api/fuota_server.go#L25

The error is gone after adding the following line:
MulticastPingSlotPeriod: uint8(req.GetDeployment().MulticastPingSlotPeriod),

[oedze]

To add to this: The MulticastPingSlotPeriod is a uint8t in the definition, but it can be a value that goes up to 4096.