Fix #6297: 🐛 Fix inline Year datepicker Keyboard Navigation Accessibility

[balajis-qb]

Description

Linked issue: #6297

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Problem

In showYearPicker mode, keyboard navigation does not visually highlight the active (focused) year when the DatePicker is rendered with inline.

This behavior is inconsistent with:

• Default DatePicker (day view)
• MonthPicker (showMonthYearPicker)

Root cause:

• isKeyboardSelected in src/year.tsx includes a !this.props.inline condition
• This prevents the react-datepicker__day--keyboard-selected class from being applied in inline mode

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Changes

• Removed the unnecessary !this.props.inline check from isKeyboardSelected
• Ensures keyboard-selected state is applied regardless of inline rendering

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Behavior Changes

• ✅ YearPicker now highlights the focused year during keyboard navigation in inline mode
• ✅ Behavior is now consistent across all picker modes
• ⚠️ No impact on non-inline behavior
• ⚠️ No changes to selection logic, only visual keyboard state handling

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Contribution checklist

• I have followed the contributing guidelines.
• I have added sufficient test coverage for my changes.
• I have formatted my code with Prettier and checked for linting issues with ESLint for code readability.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.31%. Comparing base (548a1f3) to head (f0847bf).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6299      +/-   ##
==========================================
+ Coverage   99.29%   99.31%   +0.02%     
==========================================
  Files          30       30              
  Lines        3822     3818       -4     
  Branches     1648     1645       -3     
==========================================
- Hits         3795     3792       -3     
+ Misses         26       25       -1     
  Partials        1        1              

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