Update CCS requirement to require runs to be send when availiable

[kunyavskiy]

Context: pc2ccs/pc2v9#1169

[eldering]

https://ccs-specs.icpc.io/draft/contest_api#judgements says

When a judgement is started, each of judgement_type_id, end_time and end_contest_time will be null (or missing). These are set when the judgement is completed.

This implies that a judgement should be created when judging of the submission is started and then updated when it is finished. Do we want to explicitly enforce this in the spec? That is, that all relevant runs must be present before the judgement's judgement_type_id, end_time and end_contest_time may be set?