update model IDs from text to number when applicable

[maryliag]

Is your change request related to a problem? Please describe.

Due to a limitation on weaver, IDs of model could not contain numbers, so veight was added instead of v8 on the IDs of the PR #1066, and pfifty, pninety and pninety-nine on #991

Describe the solution you'd like

Once a version of weaver that includes the fix of open-telemetry/weaver#151 is updated on this repo, the value of veight on model IDs can be updated to v8 to keep consistency with the metric name, same for using p50, p90, p99