docs(ins): fix 404

Author: bene2k1

pages/instances/reference-content/workload-optimized.mdx

@@ -46,5 +46,4 @@ To help build and manage your applications, consider complementing your Workload
 Try Scaleway Workload-Optimized Instances with the following tutorials:
 - [Setting up a MySQL database engine on Ubuntu Linux](/tutorials/setup-mysql/)
 - [Project management for technical teams with Focalboard on Ubuntu Instances](/tutorials/focalboard-project-management/)
-- [Visualizing time-Series data with TimescaleDB and Grafana](/tutorials/visualize-timeseries-data-timescaledb-grafana/)
 - [Installing a multi-node Cockroach database with HA Proxy](/tutorials/setup-cockroachdb-cluster/)

pages/managed-databases-for-postgresql-and-mysql/index.mdx

@@ -49,11 +49,7 @@ meta:
 ## Tutorials
 
 <Grid>
-    <DefaultCard
-        title="Visualizing time-Series data with TimescaleDB and Grafana"
-        url="/tutorials/visualize-timeseries-data-timescaledb-grafana/"
-        label="Read more"
-    />
+
     <DefaultCard
         title="Upgrading your Database for PostgreSQL to the latest version"
         url="/tutorials/upgrade-managed-postgresql-database/"