chore: wire up usage tracking for managed agents (#19096)

Wires up the usage collector and publisher to coderd.

Relates to coder/internal#814

coderd/files/cache_test.go

@@ -45,7 +45,6 @@ func TestCancelledFetch(t *testing.T) {
 	cache := files.New(prometheus.NewRegistry(), &coderdtest.FakeAuthorizer{})
 
 	// Cancel the context for the first call; should fail.
-	//nolint:gocritic // Unit testing
 	ctx, cancel := context.WithCancel(dbauthz.AsFileReader(testutil.Context(t, testutil.WaitShort)))
 	cancel()
 	_, err := cache.Acquire(ctx, dbM, fileID)
@@ -71,7 +70,6 @@ func TestCancelledConcurrentFetch(t *testing.T) {
 
 	cache := files.LeakCache{Cache: files.New(prometheus.NewRegistry(), &coderdtest.FakeAuthorizer{})}
 
-	//nolint:gocritic // Unit testing
 	ctx := dbauthz.AsFileReader(testutil.Context(t, testutil.WaitShort))
 
 	// Cancel the context for the first call; should fail.
@@ -99,7 +97,6 @@ func TestConcurrentFetch(t *testing.T) {
 	})
 
 	cache := files.New(prometheus.NewRegistry(), &coderdtest.FakeAuthorizer{})
-	//nolint:gocritic // Unit testing
 	ctx := dbauthz.AsFileReader(testutil.Context(t, testutil.WaitShort))
 
 	// Expect 2 calls to Acquire before we continue the test
@@ -151,7 +148,6 @@ func TestCacheRBAC(t *testing.T) {
 		Scope: rbac.ScopeAll,
 	})
 
-	//nolint:gocritic // Unit testing
 	cacheReader := dbauthz.AsFileReader(ctx)
 
 	t.Run("NoRolesOpen", func(t *testing.T) {
@@ -207,7 +203,6 @@ func cachePromMetricName(metric string) string {
 
 func TestConcurrency(t *testing.T) {
 	t.Parallel()
-	//nolint:gocritic // Unit testing
 	ctx := dbauthz.AsFileReader(t.Context())
 
 	const fileSize = 10
@@ -268,7 +263,6 @@ func TestConcurrency(t *testing.T) {
 
 func TestRelease(t *testing.T) {
 	t.Parallel()
-	//nolint:gocritic // Unit testing
 	ctx := dbauthz.AsFileReader(t.Context())
 
 	const fileSize = 10