Fix JsonExtractScalar when no value is extracted

[Jackie-Jiang]

Fix 2 bugs:

• When the json extract evaluation is pushed down, return default value when json is not well formatted or is "null"
• Preserve BIG_DECIMAL within the JSON field

[codecov-commenter]

Codecov Report

Merging #9500 (edd8cde) into master (3057712) will increase coverage by 1.31%.
The diff coverage is 70.90%.

@@             Coverage Diff              @@
##             master    #9500      +/-   ##
============================================
+ Coverage     68.66%   69.97%   +1.31%     
+ Complexity     5136     4791     -345     
============================================
  Files          1916     1917       +1     
  Lines        102069   102224     +155     
  Branches      15481    15510      +29     
============================================
+ Hits          70083    71530    +1447     
+ Misses        26980    25645    -1335     
- Partials       5006     5049      +43     

Flag	Coverage Δ
integration1	26.00% <7.27%> (-0.13%)	⬇️
integration2	24.69% <7.27%> (?)
unittests1	67.29% <70.37%> (+0.17%)	⬆️
unittests2	15.50% <40.00%> (-0.02%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
...re/common/evaluators/DefaultJsonPathEvaluator.java	34.39% <42.30%> (+2.18%)	⬆️
...pinot/query/runtime/operator/HashJoinOperator.java	82.60% <85.71%> (+0.51%)	⬆️
...thandler/SingleConnectionBrokerRequestHandler.java	88.31% <100.00%> (ø)
...a/org/apache/pinot/common/utils/PinotDataType.java	81.49% <100.00%> (+0.41%)	⬆️
...rg/apache/pinot/query/service/QueryDispatcher.java	79.00% <100.00%> (+1.58%)	⬆️
...ain/java/org/apache/pinot/spi/utils/JsonUtils.java	65.62% <100.00%> (+0.27%)	⬆️
...ntroller/helix/core/minion/TaskMetricsEmitter.java	34.88% <0.00%> (-51.17%)	⬇️
...ache/pinot/core/operator/docidsets/OrDocIdSet.java	86.36% <0.00%> (-11.37%)	⬇️
...perator/filter/SortedIndexBasedFilterOperator.java	86.66% <0.00%> (-6.67%)	⬇️
...tream/kafka20/server/KafkaDataServerStartable.java	72.91% <0.00%> (-6.25%)	⬇️
... and 162 more

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more