[FORMS-27260] Removing datepicker v2 and updating a11y fixes in v1

[muskgupta]

Description

1. v2's calendar popup (datepickerwidget.css/.js) shipped without the min/max date-range fix (Fixing date picker min max constraints. #1779) and the WCAG 1.4.10 reflow CSS (FORMS-18632: Info or functionality is unavailable at 320px width equivalent @sunnym @vavarshn #1724) that had already landed in v1, and its clientlib wasn't self-contained (hardcoded absolute image URLs and dialog extraClientlibs pointing into v1's folder). Rather than duplicating those fixes into a second component tree, this removes v2 entirely and consolidates everything back onto v1.
2. Deletes the v2 datepicker component tree (JCR content, clientlibs, Cypress spec) and rewires all resourceType/clientlib references (FormConstants, DatePickerImpl, examples, IT clientlibs, product runtime clientlib, pom.xml componentGroup visibility) back to v1.
3. Ports v2's calendar-popup accessibility improvements into v1's datepickerwidget.js: role="button" + localizable aria-label on the nav arrows, caption, and calendar-icon toggle, with per-view (Month/Year/Yearset) dynamic labels and locale translation lookups.
4. New fixes (bugs found in v2's original a11y code that we didn't just copy):

• Wired the previously-computed-but-unused caption aria-label (e.g. "January 2026") onto this.caption — v2 built this string but never applied it anywhere.
• Added aria-disabled on the caption to match its existing visual disabled state in the Yearset view, where it's role="button" but not actually clickable.

• PR that introduced v2 datepicker FORMS-18631: Desktop, RWD Tablet, RWD Mobile - Grid: Grid is missing appropriate roles and/or attributes @sunnym @vavarshn #1740

Related Issue

Motivation and Context

How Has This Been Tested?

• Verify datepicker renders/functions identically in Touch UI and rendered form
• Verify min/max date constraints still enforced
• Verify calendar popup reflows correctly at 320–400px viewport widths
• Screen-reader check: calendar icon, nav arrows, and caption announce correctly across Month/Year/Yearset views, including the disabled Yearset caption

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• I have signed the Adobe Open Source CLA.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes and the overall coverage did not decrease.
• All unit tests pass on CircleCi.
• I ran all tests locally and they pass.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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[adobe-bot]

Accessibility Violations Found

Id	Impact
aria-required-attr	critical
empty-heading	minor
label-title-only	serious
target-size	serious

[adobe-bot]

Accessibility Violations Found

Id	Impact
aria-required-attr	critical
empty-heading	minor
label-title-only	serious
target-size	serious

[adobe-bot]

Accessibility Violations Found

Id	Impact
aria-required-attr	critical
empty-heading	minor
label-title-only	serious
target-size	serious