### What this PR does / why we need it?
This is a port PR of #3636 .
Move the creation of dummy attention metadata to occur after the ACL
graph runtime mode is determined. This ensures the metadata is
initialized with the correct configuration during a profile run.
Additionally, remove the `attn_metadata` existence check before updating
MLA attention parameters. This change prevents the update from being
skipped when metadata is not yet available, ensuring parameters are set
correctly.
### Does this PR introduce _any_ user-facing change? None.
### How was this patch tested?
None.
Signed-off-by: Yizhou Liu <liu_yizhou@outlook.com>