[@mantine/dates]:DateInput component freezes the page on Safari

[kingflamez]

fixes #7441

Issue:

The original code encountered an issue when creating a dayjs object using a formatted string (dayjs(day.format('YYYY-M-D'))). This resulted in Safari producing invalid dates, leading to NaN values. This caused the while loop to continuously execute the getEndOfWeek() function, ultimately freezing the component in Safari.

Root Cause:
The format() method in dayjs converts the date to a string (ISO format), which Safari does not parse correctly in certain edge cases, especially with extreme years (e.g., 4543 as described in #7441). When re-parsed back into a dayjs object, the resulting date was invalid, causing subsequent calculations and date manipulations to fail.

Fix:

• Removed the unnecessary string formatting step, which was responsible for the invalid date in Safari.
• Replaced the .format() method with direct usage of dayjs’s native date handling methods to ensure correct date parsing and to avoid compatibility issues with Safari.

[rtivital]

Thanks!