[IMP] hr_holidays: restrict day selection by month

[anchevalier]

Before this commit, it was possible to select an invalid day for a given month in accrual plans (e.g. February 31st).

This commit introduces a dedicated field widget that dynamically restricts the available day values according to the selected month, preventing invalid selections while providing a better user experience.

Task: 6334330

[robodoo]

This PR targets the un-managed branch odoo-dev/odoo:master-hr-onboarding-chean, it needs to be retargeted before it can be merged.

[Mahmoudk3m]

Thanks for your work, left some comments 🚀

[Mahmoudk3m]

Suggested change

	const LEAP_YEAR = 2020;
	function getLastDayOfMonth(month) {
	return month
	? new Date(LEAP_YEAR, Number(month), 0).getDate()
	: 31;
	}
	export class DaySelectionByMonthField extends SelectionField {
	static props = {
	...SelectionField.props,
	selectedMonth: { type: String, optional: true },
	};
	get options() {
	const selectedMonth = this.props.record.data[this.props.selectedMonth];
	const lastDay = getLastDayOfMonth(selectedMonth);
	return super.options.filter(([day]) => day <= lastDay);
	}
	}
	export class DaySelectionByMonthField extends SelectionField {
	static props = {
	...SelectionField.props,
	selectedMonth: { type: String, optional: true },
	};
	get options() {
	const selectedMonth = this.props.record.data[this.props.selectedMonth];
	const allDays = this.props.record.fields[this.props.name].selection;
	const maxDays = new Date(2024, month, 0).getDate();
	return allDays.filter(opt => parseInt(opt[0]) <= maxDays);
	}
	}

Maybe we could do something like this instead?

[anchevalier]

This approach could work after replacing month with selectedMonth, but I would keep using super.options here since it already exposes the field selection from the base SelectionField. I would also keep the LEAP_YEAR constant, or at least add a comment, to avoid having 2024 as a magic number.