[fix][CGS][entrance] parallelgroup cache not updated when entrance instance goes offline

[v-kkhuang]

What is the purpose of the change

Background/Problem:
When an Entrance instance goes offline, the ParallelGroup cache is not updated. This causes incorrect calculation of user task concurrency, affecting task scheduling and resource management in multi-instance deployments.

Purpose of Change:
To address this problem, this PR fixes the cache update mechanism and adds exception handling to ensure the ParallelGroup cache is properly maintained when Entrance instances change state.

Value/Impact:
After the change, task concurrency calculation remains accurate even when Entrance instances go online or offline, improving system stability and resource utilization efficiency.

Related issues/PRs

Related issues: close #965
Related pr:none

Brief change log

• Fix ParallelGroup cache update when Entrance instance goes offline
• Add exception protection in Entrance scheduler components
• Update concurrency calculation logic for multi-instance scenarios

Checklist

• I have read the Contributing Guidelines on pull requests.
• I have explained the need for this PR and the problem it solves
• I have explained the changes or the new features added to this PR
• I have added tests corresponding to this change
• I have updated the documentation to reflect this change
• I have verified that this change is backward compatible
• If this is a code change: I have written unit tests to fully verify the new behavior.

[casionone]

LGTM.