Handle errors gracefully during multi-stage stats collection in the broker

[yashmayya]

• There exist certain edge cases during multi-stage stats collection at the broker that can result in exceptions because the stats are generated by the physical operators but the info available to construct the tree is the logical operators.
• Currently, any such exceptions will propagate all the way up to here and will result in the query failing.
• Instead, we should log the error and indicate it in the stats response while still returning the actual query results.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 0% with 13 lines in your changes missing coverage. Please review.

Project coverage is 35.27%. Comparing base (59551e4) to head (0026e3c).
Report is 683 commits behind head on master.

Files	Patch %	Lines
...requesthandler/MultiStageBrokerRequestHandler.java	0.00%	13 Missing ⚠️

❗ There is a different number of reports uploaded between BASE (59551e4) and HEAD (0026e3c). Click for more details.

HEAD has 26 uploads less than BASE

| Flag | BASE (59551e4) | HEAD (0026e3c) | |------|------|------| |integration|7|5| |temurin|12|6| |java-21|7|5| |skip-bytebuffers-false|7|2| |unittests|5|1| |unittests1|2|1| |java-11|5|1| |integration1|2|1| |custom-integration1|2|1|

Additional details and impacted files

@@              Coverage Diff              @@
##             master   #13496       +/-   ##
=============================================
- Coverage     61.75%   35.27%   -26.48%     
+ Complexity      207        6      -201     
=============================================
  Files          2436     2484       +48     
  Lines        133233   137678     +4445     
  Branches      20636    21372      +736     
=============================================
- Hits          82274    48570    -33704     
- Misses        44911    85422    +40511     
+ Partials       6048     3686     -2362     

Flag	Coverage Δ
custom-integration1	<0.01% <0.00%> (-0.01%)	⬇️
integration	<0.01% <0.00%> (-0.01%)	⬇️
integration1	<0.01% <0.00%> (-0.01%)	⬇️
integration2	0.00% <0.00%> (ø)
java-11	0.00% <0.00%> (-61.71%)	⬇️
java-21	35.27% <0.00%> (-26.35%)	⬇️
skip-bytebuffers-false	0.00% <0.00%> (-61.75%)	⬇️
skip-bytebuffers-true	35.27% <0.00%> (+7.55%)	⬆️
temurin	35.27% <0.00%> (-26.48%)	⬇️
unittests	46.51% <ø> (-15.24%)	⬇️
unittests1	46.51% <ø> (-0.38%)	⬇️
unittests2	?

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