[2.4.0] Checkmk Werk 16370 created: time_periods: Fix error when using time ranges shorter than a minute

[//]: # (werk v2) # time_periods: Fix error when using time ranges shorter than a minute key | value ---------- | --- date | 2024-02-22T10:48:51+00:00 version | 2.4.0b1 class | fix edition | cre component | rest-api level | 1 compatible | yes Prior to this Werk, when trying to create a time period with a time range shorter than 1 minute, an error code 500 was returned due to a validation error. This Werk solves that problem, and time periods shorter than 1 minute are validated correctly, so the endpoint now accepts them.