fix: only collect prometheus database metrics when explicitly enabled (#8045)

* fix: only collect prometheus database metrics when explicitly enabled

* add missing test

* de-duplicate wrapping

coderd/apidoc/docs.go

@@ -7880,6 +7880,9 @@ const docTemplate = `{
                 "collect_agent_stats": {
                     "type": "boolean"
                 },
+                "collect_db_metrics": {
+                    "type": "boolean"
+                },
                 "enable": {
                     "type": "boolean"
                 }

coderd/apidoc/swagger.json

@@ -7061,6 +7061,9 @@
         "collect_agent_stats": {
           "type": "boolean"
         },
+        "collect_db_metrics": {
+          "type": "boolean"
+        },
         "enable": {
           "type": "boolean"
         }

coderd/coderd.go

@@ -47,7 +47,6 @@ import (
 	"github.com/coder/coder/coderd/awsidentity"
 	"github.com/coder/coder/coderd/database"
 	"github.com/coder/coder/coderd/database/dbauthz"
-	"github.com/coder/coder/coderd/database/dbmetrics"
 	"github.com/coder/coder/coderd/database/pubsub"
 	"github.com/coder/coder/coderd/gitauth"
 	"github.com/coder/coder/coderd/gitsshkey"
@@ -191,10 +190,6 @@ func New(options *Options) *API {
 	if options.Authorizer == nil {
 		options.Authorizer = rbac.NewCachingAuthorizer(options.PrometheusRegistry)
 	}
-	// The below are no-ops if already wrapped.
-	if options.PrometheusRegistry != nil {
-		options.Database = dbmetrics.New(options.Database, options.PrometheusRegistry)
-	}
 	options.Database = dbauthz.New(
 		options.Database,
 		options.Authorizer,