Circumvent cache in WIC->Ethics sync

[gregorbg]

This is (unfortunately) a very obscure fix, because the use-case is already a hack in itself.

WIC is the first team ever (to my knowledge) where two teams were merged into one (originally WDC and WEC). They want access to the historic records in both email groups, but we only support one-to-one sync.

When WIC was introduced, it was decided that they will become a rename of WDC. So they have automatic stuff to all WDC history. But they also want and need to be synced to ethics@ which is the old WEC group. We do that sync manually with a hand-crafted line of code.

The problem is that this code directly accesses the GroupsMetadataTeamsCommittees.wic shorthand. These shorthands are cached, so if the leader adds new members the list sync will not consider them until the next deploy (or reboot) which can sometimes be days apart.

This PR fixes that small inconvenience by using pluck which forces Rails to directly fire an SQL query every single time.