feat: Support ANSI mode SUM (Decimal types)

[coderfender]

Which issue does this PR close?

Closed #531 (Adds ANSI support for decimal inputs)

Rationale for this change

1. Changes to add ANSI and Try eval mode support to Decimal Sums
2. The code already has support to identify overflow and the changes are essentially passing in eval mode and raising an error when there is an overflow. (is_null , is_empty flags). The only update here is to consolidate the state variables to 2 (optional i128 and an is_null flag). Unlike int sum, spark leverages both the sum and is_empty state vars in all modes

What changes are included in this PR?

1. Changes to SumDecimal
2. CometSum update to support ANSI mode
3. Unit tests (and fix existing tests)

How are these changes tested?

1. Unit test on scala side

[coderfender]

@andygrove , Please kickoff CI whenever get a chance . This PR should essentially finish impl ANSI (along with #2600 ) for all numeric types

[codecov-commenter]

Codecov Report

❌ Patch coverage is 40.00000% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 58.72%. Comparing base (f09f8af) to head (272b661).
⚠️ Report is 728 commits behind head on main.

Files with missing lines	Patch %	Lines
...main/scala/org/apache/comet/serde/aggregates.scala	40.00%	1 Missing and 2 partials ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #2826      +/-   ##
============================================
+ Coverage     56.12%   58.72%   +2.60%     
- Complexity      976     1463     +487     
============================================
  Files           119      167      +48     
  Lines         11743    15175    +3432     
  Branches       2251     2498     +247     
============================================
+ Hits           6591     8912    +2321     
- Misses         4012     4958     +946     
- Partials       1140     1305     +165     

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[coderfender]

Fixed test failures by converting state variables into option and is_empty as per spark semantics . @andygrove , Please kickoff CI whenever you get a chance.

[coderfender]

Fixed scala 2.13 formatting failures