Checkmk Werk 15415: Interface checks: Fix errors in perfometer rendering

ID: 15415 Title: Interface checks: Fix errors in perfometer rendering Component: Checks & agents Level: 1 Class: Bug fix Version: 2.3.0b1 This issue only affected network interface services. After discovering new services or after an update, the user interface initially displayed `Exception: list index out of range` in the place where the perfometer is supposed to be displayed. The log file <i>var/log/web.log</i> also recorded these errors: C+: 2023-04-11 10:00:28,884 [40] [cmk.web 78582] error rendering performeter Traceback (most recent call last): ... IndexError: list index out of range C-: These errors quickly disappeared after a couple of check cycles. As of this werk, these error messages are not displayed anymore. Instead, the perfometer is rendered as soon as all necessary metrics are found.