[KIP-848] Fix static group membership

[emasab]

trafficstars

there are three cases for static group membership this PR fixes the first one:

• member explicitly unsubscribes -> should cause a rebalance
• member closes the consumer -> no rebalance
• member destroys the consumer -> no rebalance

When a new member joins the group and there's already a member with same group instance id that hasn't left statically the new member is fenced with the new protocol

[!WARNING] The test won't work until regex implementation is merged

[confluent-cla-assistant[bot]]

:tada: All Contributor License Agreements have been signed. Ready to merge.
_{Please push an empty commit if you would like to re-run the checks to verify CLA status for all contributors.}