chore(deps): update grafana monorepo to v11.6.8

| datasource | package          | from   | to     |
| ---------- | ---------------- | ------ | ------ |
| npm        | @grafana/data    | 11.6.0 | 11.6.8 |
| npm        | @grafana/runtime | 11.6.0 | 11.6.8 |
| npm        | @grafana/schema  | 11.6.0 | 11.6.8 |
| npm        | @grafana/ui      | 11.6.0 | 11.6.8 |


Signed-off-by: renovate-sh-app[bot] <219655108+renovate-sh-app[bot]@users.noreply.github.com>

Author: renovate-sh-app[bot]