ICS with inactive provider validators: Top N chains need an active set size cap or disable inactive provider validators

[p-offtermatt]

Summary

Top N chains should have an active set size cap once inactive provider validators are allowed to validate on them.
Without an active set size cap, those chains would potentially have an arbitrary number of validators.
Additionally, the active set size cap must not be smaller than the MaxProviderConsensusValidators, because of issues around
validators being forced to keep their nodes for the chain running without having an option to get rewards.

An alternative would be to make it so top N chains disable the inactive provider validator feature completely.

Closing criteria

The inactive validator set feature has a mitigation for this problem implemented.