### What this PR does / why we need it?
Fix mooncake layerconnector dead when update_decoder_info fail. For the
scenario where node D is dead, node P failing to update_decoder_info
should not cause node P to become dead.
### Does this PR introduce _any_ user-facing change?
### How was this patch tested?
by CI
- vLLM version: v0.17.0
- vLLM main:
8b6325758c
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Signed-off-by: liziyu <liziyu16@huawei.com>