[fix][broker] Fix broker immediately redirect migration eligible consumers

[rdhabalia]

Motivation

Right now, when broker marks topic migrated during blue-green cluster migration then broker disconnects consumers of the subscriptions once it reaches end of managed-leger data and consumer will be redirected to green cluster. However, if consumer is connected to topic without any backlog then consumer stays connected and broker didn't trigger consumer migration or it delays newly connected consumers which are eligible to redirect to new green cluster. Therefore, this PR makes sure that all the consumers of subscriptions which are not having backlog will be migrated and broker also checks topic migration when new consumer connects and notifies those consumers immediately if there is no backlog on that subscription.

Result

Consumers will be redirected to migrated cluster immediately if the subscription doesn't have any backlog.

Does this pull request potentially affect one of the following parts:

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• Dependencies (add or upgrade a dependency)
• The public API
• The schema
• The default values of configurations
• The threading model
• The binary protocol
• The REST endpoints
• The admin CLI options
• The metrics
• Anything that affects deployment

Documentation

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• doc-not-needed
• doc-complete

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