fix: restore dp-input model binding for formats with MMM/MMMM tokens

[kouts]

Describe your changes

This PR fixes a regression introduced in v12.1.0 where using the dp-input slot with formats containing alphabetic tokens (like MMM for month abbreviation) no longer updates the model value.

Root cause: The getPatternForValue function (added in commit 572c401 to fix #1208) used /\D+/g to split input values. This incorrectly treated alphabetic parts like "Dec" in 18-Dec-2025 as separators instead of date values.

Solution: Simplified the parsing logic by:

• Trying the full pattern first
• Falling back to a sliced pattern for partial input
• Removed the complex getPatternForValue and hasAlphabeticTokens functions

Additional improvements:

• Extracted pure parsing functions to useTextInputUtils.ts for better testability
• Added comprehensive unit tests for tryParseDate, parseDateWithPattern, createMaskedValue, and applyMaxValues

Tested scenarios:

• dd-MMM-yyyy format (e.g., 18-Dec-2025) → Model updates correctly ✅
• dd-MM-yy short year format (e.g., 18-12-25) → Still works ✅
• All existing tests pass ✅

Issue ticket number and link

Fixes #1222

Checklist before requesting a review

• I have performed a self-review of my code
• I have ensured that unit tests pass without errors
• If it is a new feature, I have added a new unit test

[m-anwr]

Awesome fix 👍