2.2.40

## What's Changed
* [OPIK-8021] [FE] perf: virtualize the experiment results table by @andriidudar in https://github.com/comet-ml/opik/pull/7977
* [OPIK-7686] [DOCS] Document where the async-insert cutover bump lives by @thiagohora in https://github.com/comet-ml/opik/pull/7916
* [OPIK-6901] [BE] perf: prune trace deletes to the batch's own partitions by @thiagohora in https://github.com/comet-ml/opik/pull/7912
* build(deps): bump actions/download-artifact from 4 to 8 by @dependabot[bot] in https://github.com/comet-ml/opik/pull/7820
* build(deps): bump losisin/helm-docs-github-action from 1 to 2 by @dependabot[bot] in https://github.com/comet-ml/opik/pull/7821
* build(deps): bump azure/setup-helm from 4.3.1 to 5.0.1 by @dependabot[bot] in https://github.com/comet-ml/opik/pull/7824
* [OPIK-7772] [BE] test: guard traces DDL across pre/post-cutover topologies in CI by @thiagohora in https://github.com/comet-ml/opik/pull/7951
* [OPIK-8045] [BE] fix: four online-scoring failures seen in production by @thiagohora in https://github.com/comet-ml/opik/pull/7949
* [OPIK-8040] [BE] fix: apply online evaluation sampling to production traces only by @jverre in https://github.com/comet-ml/opik/pull/7957
* [OPIK-7940] [BE] [FE] feat: dynamic token auth (OAuth2 client credentials) for custom AI providers by @miguelgrc in https://github.com/comet-ml/opik/pull/7910
* [OPIK-7940] [FE] [CI] test: e2e coverage for OAuth2 dynamic token auth by @miguelgrc in https://github.com/comet-ml/opik/pull/7914


**Full Changelog**: https://github.com/comet-ml/opik/compare/2.2.39...2.2.40