[Enhancement] Restrict system subscription group creation and add pull request rejection policy

[ymwneu]

Before Creating the Enhancement Request

• I have confirmed that this should be classified as an enhancement rather than a bug/feature.

Summary

1. When the "rejectPullConsumerEnable" configuration is enabled, restrict pull requests when pulling messages.
2. Automatic creation and addition of switch recognition for subscription groups to prevent abuse of system subscriptions.

Motivation

1. When the rejectPullConsumerEnable configuration is enabled, it is designed to reject pull requests during pullMessage operations. However, while this switch exists in the open-source code, it is currently not properly implemented or utilized in practice.
2. Currently, the creation of topics and CIDs are both controlled by a switch, and in many scenarios, this control is indeed necessary. However, the creation of system CIDs has not been subject to control. The potential risk is that some users might exploit this loophole to bypass control and create numerous system CIDs. The increase in metadata volume could lead to larger registerBroker requests, posing a stability risk.

Describe the Solution You'd Like

1. When the "rejectPullConsumerEnable" configuration is enabled, restrict pull requests when pulling messages.
2. Add a new "enableCreateSysGroup" switch to control the creation of system CIDs.

Describe Alternatives You've Considered

no

Additional Context

No response