test: change of pool owner should not allow double voting

[gabririgo]

This is currently now allowed by design as:

1. pool operator cannot be changed in staking pool
2. each pool's vote is stored, voting power is computed at sigle wallet/smart-wallet level and not aggregated level (i.e. pool operator).

However, we should develop a test to assert that a change in the pool operator won't affect ability to vote and won't allow double voting. This is relevant in the case we will query staking pool data from registry and pool, instead of initializing the staking pool, for gas efficiency (this will however affect ability to set staking pal, which is a feature which is not particularly requested anyway).

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[stale]

This issue has been automatically closed because no activity occured in 30 days after being marked as stale. If it's still relevant - feel free to reopen. Thank you for your contributions.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.