Cert-expiry component on domain of the hass instance can't connect yet in startup

@fabfurnari

Home Assistant release (hass --version):

Component/platform:

Description of problem:

When using this component on the IP of the home assistant instance, the first refresh happens while the server isn't available yet and fails with [homeassistant.components.sensor.cert_expiry] Cannot connect to <domain>. As a result, the UI shows unknown days for the first 12 hours (until another refresh happens).

Expected:

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