[Improve][Manager] Enable Manager to use multiple scheduling engines simultaneously

[Zkplo]

Description

org.apache.inlong.manager.service.schedule.ScheduleOperatorImpl

private ScheduleEngineClient getScheduleEngineClient(String scheduleEngine) {
    if (scheduleEngineClient == null) {
        scheduleEngineClient = scheduleClientFactory.getInstance(scheduleEngine);
    }
    return scheduleEngineClient;
}

At present, the single instance mode is adopted. When a user selects any scheduling engine from the front-end to issue offline tasks, the subsequent selection of the scheduling engine will follow the first one, and there is a possibility of scheduling engine selection failure.In order to support multiple scheduling engines, it is necessary to modify the code logic here.

InLong Component

InLong Manager

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• Yes, I am willing to submit a PR!

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