fix: fall back on nested types for default values

[mbutrovich]

Which issue does this PR close?

Partially address #1545.

Rationale for this change

#1756 added default value support for native_datafusion scan. However, this only works for Literals. If the default values are nested types, we can't yet serialize those to the native side for the scan operator to use. This PR adds a fallback for that scenario.

What changes are included in this PR?

Enhanced CometScanRule to look for default values that are not Literals.

How are these changes tested?

Now passes Spark SQL tests:

• SPARK-39557 INSERT INTO statements with tables with array defaults
• SPARK-39557 INSERT INTO statements with tables with struct defaults
• SPARK-39557 INSERT INTO statements with tables with map defaults

[andygrove]

Thanks @mbutrovich

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 25.00000% with 6 lines in your changes missing coverage. Please review.

Project coverage is 59.44%. Comparing base (f09f8af) to head (c6ee979).
Report is 220 commits behind head on main.

Files with missing lines	Patch %	Lines
...n/scala/org/apache/comet/rules/CometScanRule.scala	25.00%	3 Missing and 3 partials ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #1799      +/-   ##
============================================
+ Coverage     56.12%   59.44%   +3.31%     
- Complexity      976     1143     +167     
============================================
  Files           119      128       +9     
  Lines         11743    12538     +795     
  Branches       2251     2357     +106     
============================================
+ Hits           6591     7453     +862     
+ Misses         4012     3892     -120     
- Partials       1140     1193      +53     

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[parthchandra]

lgtm