Improve session cleanup (#18123)

- We move logging statements to the upper layer.
Store functions are low-level methods and should return error
upwards rather than logging.
- Used IN instead of any (array ()) which is equivalent.
- Made the delay to be of type time.Duration and un-exported it.
- Unexported the batch size constant.

```release-note
NONE
```

store/storetest/mocks/SessionStore.go

@@ -38,8 +38,17 @@ func (_m *SessionStore) AnalyticsSessionCount() (int64, error) {
 }
 
 // Cleanup provides a mock function with given fields: expiryTime, batchSize
-func (_m *SessionStore) Cleanup(expiryTime int64, batchSize int64) {
-	_m.Called(expiryTime, batchSize)
+func (_m *SessionStore) Cleanup(expiryTime int64, batchSize int64) error {
+	ret := _m.Called(expiryTime, batchSize)
+
+	var r0 error
+	if rf, ok := ret.Get(0).(func(int64, int64) error); ok {
+		r0 = rf(expiryTime, batchSize)
+	} else {
+		r0 = ret.Error(0)
+	}
+
+	return r0
 }
 
 // Get provides a mock function with given fields: ctx, sessionIDOrToken

store/storetest/session_store.go

@@ -303,7 +303,8 @@ func testSessionCleanup(t *testing.T, ss store.Store) {
 	s4, err = ss.Session().Save(s4)
 	require.NoError(t, err)
 
-	ss.Session().Cleanup(now, 1)
+	err = ss.Session().Cleanup(now, 1)
+	require.NoError(t, err)
 
 	_, err = ss.Session().Get(context.Background(), s1.Id)
 	assert.NoError(t, err)