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1. As the AlterPartition and Fetch requests are shared between ZK and Kraft mode, we can just let the ZK controller ignore the broker epoch field.
2. The metadata version/IBP version will be bumped. During the upgrade, leaders will leave the broker epoch field as -1 if the broker has not upgraded yet. The controller will skip the validation if the epoch is -1.

Test Plan

Will include system tests to simulate test by simulating the race scenario between of the broker registration delayed AlterPartitionRequest and the delayed AlterPartition requestbroker reboot.

Rejected Alternatives

Bump all the partition leader epochs when a broker registers.

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