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 60.00000% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 59.17%. Comparing base (f09f8af) to head (ab437f5).
⚠️ Report is 730 commits behind head on main.

Files with missing lines	Patch %	Lines
...main/scala/org/apache/comet/serde/aggregates.scala	60.00%	0 Missing and 2 partials ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #2826      +/-   ##
============================================
+ Coverage     56.12%   59.17%   +3.05%     
- Complexity      976     1478     +502     
============================================
  Files           119      167      +48     
  Lines         11743    15188    +3445     
  Branches       2251     2522     +271     
============================================
+ Hits           6591     8988    +2397     
- Misses         4012     4916     +904     
- Partials       1140     1284     +144     

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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

[martin-g]

LGTM

[coderfender]

Thank you for the approval @martin-g

[andygrove]

I don't think these tests need to set CometConf.getExprAllowIncompatConfigKey(classOf[Sum]) -> "true"?

[andygrove]

Thanks @coderfender. One nit - the tests shouldn't be setting CometConf.getExprAllowIncompatConfigKey(classOf[Sum]) -> "true" so would be good to remove those lines.

[andygrove]

Thanks @coderfender. One nit - the tests shouldn't be setting CometConf.getExprAllowIncompatConfigKey(classOf[Sum]) -> "true" so would be good to remove those lines.

This can be done in a separate PR

[andygrove]

Thanks for the review @martin-g