### What this PR does / why we need it? This PR is cherry-pick from #8263. This PR aims to fix short prompt problem. The root cause can be found in #8029. Since the previous pr may miss mixed long and short prompt batch, after discussion, we decide to add PrefillNoCache state in mla _forward_decode now instead. Signed-off-by: Zetong Li <slippersss@126.com>