fix(date): return Date instead of number

[Kundan-CR7]

What kind of change does this PR introduce?

• Bugfix
• Feature
• Documentation
• Code style update
• Refactor
• Build-related changes
• Other, please describe:

fixes #18260
Does this PR introduce a breaking change?

• Yes
• No

The PR fulfills these requirements:

• It's submitted to the dev branch (or v[X] branch)
• When resolving a specific issue, it's referenced in the PR's title (e.g. fix: #<issue-number>)
• It's been tested on a Cordova (iOS, Android) app
• It's been tested on an Electron app
• Any necessary documentation has been added or updated

---

Problem

getMaxDate and getMinDate currently return a numeric timestamp instead of a Date object.

This happens because Math.max() / Math.min() convert Date objects into timestamps.

Example:

const d1 = new Date('2024-01-01')
const d2 = new Date('2024-06-01')

const result = date.getMaxDate(d1, d2)

console.log(typeof result) // number
console.log(result instanceof Date) // false

result.getFullYear() // TypeError

[rstoenescu]

Thanks for contributing!