feat: add literal constraints to type signatures

[getChan]

Which issue does this PR close?

• Closes A way to specify constant/scalar arguments in UDFs #24133.

Rationale for this change

Some functions require particular arguments to be literal values. This requirement is currently enforced separately by each function, rather than being declared as part of the function signature.

What changes are included in this PR?

• Adds ArgumentConstraint and TypeSignature::Constrained.
• Validates literal constraints while logical expressions are analyzed and typed.
• Declares the required literal arguments for arrow_cast, arrow_try_cast, and date_part.
• Keeps expression constraints separate from Coercion.

Are these changes tested?

Yes.

• Added a unit test covering accepted and rejected literal constraints.
• Ran ./dev/rust_lint.sh.
• Ran the existing DataFrame arrow_cast integration test.

Are there any user-facing changes?

Calls to constrained functions with non-literal arguments are rejected consistently during planning. This PR also adds public signature API types and therefore may require the api change label.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 96.80851% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 81.06%. Comparing base (b225ded) to head (16b4db1).
⚠️ Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
datafusion/expr-common/src/signature.rs	95.83%	1 Missing ⚠️
datafusion/expr/src/type_coercion/functions.rs	97.82%	1 Missing ⚠️
datafusion/optimizer/src/analyzer/type_coercion.rs	80.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #24201      +/-   ##
==========================================
- Coverage   81.06%   81.06%   -0.01%     
==========================================
  Files        1106     1106              
  Lines      381847   381936      +89     
  Branches   381847   381936      +89     
==========================================
+ Hits       309541   309613      +72     
- Misses      54036    54048      +12     
- Partials    18270    18275       +5     

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