fix: coerce decimal literals in target subset filters

[ethan-tyler]

Description

Found this while working on #4266.

Merge target subset filters can retain decimal precision/scale from the source expression instead of the target schema. For example decimal(4, 1) when the column is decimal(6, 1). The newer file skipping path rejects the mismatch.

This fix is normalize target_subset_filter against the target schema before simplification, and extend literal coercion to handle between bounds.

Related Issue(s)

Documentation

[codecov]

Codecov Report

❌ Patch coverage is 85.50725% with 10 lines in your changes missing coverage. Please review.
✅ Project coverage is 76.85%. Comparing base (ca0f37e) to head (5e589b5).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
crates/core/src/delta_datafusion/utils.rs	86.66%	3 Missing and 3 partials ⚠️
crates/core/src/operations/merge/mod.rs	83.33%	2 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4267      +/-   ##
==========================================
- Coverage   76.85%   76.85%   -0.01%     
==========================================
  Files         167      167              
  Lines       49098    49139      +41     
  Branches    49098    49139      +41     
==========================================
+ Hits        37735    37766      +31     
- Misses       9453     9459       +6     
- Partials     1910     1914       +4     

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