In `VoteKickPolicy.onFlag()`, `targetStakeAtRiskWei[target]` might be greater than `stakedWei[target]` and `_endVote()` would revert.
`targetStakeAtRiskWei[target]` might be greater than `stakedWei[target]` in `onFlag()`.\\n```\\ntargetStakeAtRiskWei[target] = max(stakedWei[target], streamrConfig.minimumStakeWei()) * streamrConfig.slashingFraction() / 1 ether;\\n```\\n\\nFor example,\\nAt the first time, `streamrConfig.minimumStakeWei()` = 100 and an operator(=target) has staked 100.\\n`streamrConfig.minimumStakeWei()` was increased to 2000 after a reconfiguration.\\n`onFlag()` is called for target and `targetStakeAtRiskWei[target]` will be `max(100, 2000) * 10% = 200`.\\nIn `_endVote()`, `slashingWei = _kick(target, slashingWei)` will be 100 because target has staked 100 only.\\nSo it will revert due to underflow during the reward distribution.
`onFlag()` should check if a target has staked enough funds for rewards and handle separately if not.
Operators with small staked funds wouldn't be kicked forever.
```\\ntargetStakeAtRiskWei[target] = max(stakedWei[target], streamrConfig.minimumStakeWei()) * streamrConfig.slashingFraction() / 1 ether;\\n```\\n