feat: add prometheus metrics to database.Store (#7713)

* Adds dbmetrics package and wraps database.Store with a Prometheus HistogramVec of timings.
* Adds Wrappers method to database.Store to avoid double-wrapping interfaces
* Fixes test flake in TestLicensesListFake

enterprise/cli/licenses_test.go

@@ -140,6 +140,7 @@ func TestLicensesListFake(t *testing.T) {
 	// so instead we have to fake the HTTP interaction.
 	t.Run("Mainline", func(t *testing.T) {
 		t.Parallel()
+		expectedLicenseExpires := time.Date(2024, 4, 6, 16, 53, 35, 0, time.UTC)
 		ctx, cancel := context.WithTimeout(context.Background(), testutil.WaitLong)
 		defer cancel()
 		inv := setupFakeLicenseServerTest(t, "licenses", "list")
@@ -158,7 +159,13 @@ func TestLicensesListFake(t *testing.T) {
 		assert.Equal(t, "claim1", licenses[0].Claims["h1"])
 		assert.Equal(t, int32(5), licenses[1].ID)
 		assert.Equal(t, "claim2", licenses[1].Claims["h2"])
-		assert.Equal(t, "2024-04-06T16:53:35Z", licenses[0].Claims["license_expires"])
+		expiresClaim := licenses[0].Claims["license_expires"]
+		expiresString, ok := expiresClaim.(string)
+		require.True(t, ok, "license_expires claim is not a string")
+		assert.NotEmpty(t, expiresClaim)
+		expiresTime, err := time.Parse(time.RFC3339, expiresString)
+		require.NoError(t, err)
+		require.Equal(t, expectedLicenseExpires, expiresTime.UTC())
 	})
 }