avoid using Lazy for metrics

[skyzh]

Steps to reproduce

Currently, we are using Lazy for all metrics, but if we do not access that metric, it will not appear in the exporter.

Expected result

Actual result

Environment

Logs, links

[skyzh]

Given we will need to pass a global object everywhere if we remove Lazy, this is not an optimal way to fix it. Currently we are solving this by adding access metrics in pre-initialize.

[skyzh]

The intention of this issue is that there is a test case that checks if a metrics is available when a tenant is attached and removed when a tenant is detached. For page cache metrics, it is hard to have page hit in tests and therefore it is not available immediately when a tenant is created.

[skyzh]

now tracked here #4813