[containerapp] Container Apps logs in follow mode exit after not receiving new logs for a few minutes

Source: https://github.com/Azure/azure-cli/issues/33487 (by @catmanjan)
Affected extension: `containerapp` (`src/containerapp/`)

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# Issue #33487 (by @catmanjan)
## Title
Container Apps logs in follow mode exit after not receiving new logs for a few minutes

## Body
### Describe the bug

Similar to https://github.com/Azure/azure-cli/issues/28267

I am following container logs like so

az containerapp logs show --n cmlinux -g cmlinux --follow --tail 30

The container is intentionally quiet in logging, after approximately 3 minutes the log command just stops

### Related command

az containerapp logs show --n cmlinux -g cmlinux --follow --tail 30

### Errors

N/A

### Issue script & Debug output

az containerapp logs show --n cmlinux -g cmlinux --follow --tail 30

{"TimeStamp": "2026-06-03T04:45:59.2214149+00:00", "Log": "F 013c:fixme:file:NtFsControlFile FSCTL_PIPE_IMPERSONATE: impersonating self"}
{"TimeStamp": "2026-06-03T04:48:25.34888", "Log": "No logs since last 60 seconds"}
{"TimeStamp": "2026-06-03T04:49:25.74618", "Log": "No logs since last 60 seconds"}
{"TimeStamp": "2026-06-03T04:50:26.18445", "Log": "No logs since last 60 seconds"}
{"TimeStamp": "2026-06-03T04:51:26.71221", "Log": "No logs since last 60 seconds"}
sysadmin@nuc:~$

### Expected behavior

Should tail forever

### Environment Summary

azure-cli 2.87.0

Can also reproduce it in browser

### Additional context

_No response_

## Comments
### Comment by @yonzhan

Thank you for opening this issue, we will look into it.
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