PageSize missing from HugetlbStats

Hugepage may have different sizes，e.g. 2MB,1GB, the data carried by HugetlbStats is insufficient to provide the real hugepage information. HugetlbStats defined in https://github.com/opencontainers/runc/blob/main/libcontainer/cgroups/stats.go#L138, and PageSize is missing from HugetlbStats. on the other hand, https://github.com/containerd/cgroups/blob/main/stats/v1/metrics.proto#L23 has cantain pagesize already.

take containerd to show the issue, https://github.com/containerd/containerd/blob/main/metrics/cgroups/v1/hugetlb.go#L43 use the pagesize, but pagesize is empty, because libcontainer don't give pagesize infomation, containerd will get two metrics for one container(one metrics for 2MB, one metrics for 1GB),and the two metrics have same value, this will lead prometheus error:

An error has occurred while serving metrics:

42 error(s) occurred:
* collected metric "container_hugetlb_usage_bytes" { label:<name:"container_id" value:"21a24f24209904b7eddf3b2b4315462e2c38a3c81da48400aecc4022f4403e63" > label:<name:"namespace" value:"k8s.io" > label:<name:"page" value:"" > gauge:<value:0 > } was collected before with the same name and label values
* collected metric "container_hugetlb_failcnt_total" { label:<name:"container_id" value:"21a24f24209904b7eddf3b2b4315462e2c38a3c81da48400aecc4022f4403e63" > label:<name:"namespace" value:"k8s.io" > label:<name:"page" value:"" > gauge:<value:0 > } was collected before with the same name and label values
* collected metric "container_hugetlb_max_bytes" { label:<name:"container_id" value:"21a24f24209904b7eddf3b2b4315462e2c38a3c81da48400aecc4022f4403e63" > label:<name:"namespace" value:"k8s.io" > label:<name:"page" value:"" > gauge:<value:0 > } was collected before with the same name and label values
...

Start with libcontainer/cgroups/stats.go at the HugetlbStats definition, then compare the related metrics.proto and containerd hugetlb.go references named in the issue. Trace how hugepage statistics are populated and confirm that distinct 2MB and 1GB pages retain their page-size information. Done means consumers no longer receive duplicate empty page labels for different hugepage sizes.