not have rocketmq_ group_ get_ latency

**Describe the bug**
The new version does not have rocketmq_ group_ get_ latency，I'd like to know if my consumer group has any delay and should look at that indicator，rocketmq_ group_ get_ latency_ by_ storetime is not the consumption delay of the client

**To Reproduce**
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4. See error

**Expected behavior**
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**Screenshots**
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**Desktop (please complete the following information):**
- OS: [e.g. iOS]
- Browser [e.g. chrome, safari]
- Version [e.g. 22]

**Smartphone (please complete the following information):**
- Device: [e.g. iPhone6]
- OS: [e.g. iOS8.1]
- Browser [e.g. stock browser, safari]
- Version [e.g. 22]

**Additional context**
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