All Websites dashboard accepts invalid dates

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The All Websites dashboard accepts invalid dates via URL parameters as per the examples below

https://demo.matomo.cloud/index.php?module=MultiSites&action=index&idSite=2&period=day&date=2024-02-31
takes an invalid date and handles it as the 3rd of March

https://demo.matomo.cloud/index.php?module=MultiSites&action=index&idSite=2&period=day&date=2024-09-31
takes an invalid date and handles it as the 1st of October

The JavaScript datepicker shows an error but the back end still processes the date and shows analytics for the handled date.

This is a bit of a edge case but we should probably throw an exception or display a warning.