Fix the 'ExplainPlanQueriesTest' to use the new SET format for the verbose explain plan option

[somandal]

This PR fixes up the 'ExplainPlanQueriesTest' to use the new SET format for setting the query options for the Explain Plan verbose option.

E.g.

SET explainPlanVerbose=true;
EXPLAIN PLAN FOR SELECT * FROM testTable

cc @siddharthteotia

[siddharthteotia]

Thanks for the changes.

[codecov-commenter]

Codecov Report

Merging #9048 (6b6a0f2) into master (25ead8d) will increase coverage by 0.49%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master    #9048      +/-   ##
============================================
+ Coverage     68.43%   68.92%   +0.49%     
- Complexity     4737     4953     +216     
============================================
  Files          1831     1831              
  Lines         96270    96270              
  Branches      14390    14390              
============================================
+ Hits          65879    66354     +475     
+ Misses        25811    25299     -512     
- Partials       4580     4617      +37     

Flag	Coverage Δ
integration1	26.61% <ø> (?)
integration2	?
unittests1	66.85% <ø> (-0.01%)	⬇️
unittests2	15.38% <ø> (+0.02%)	⬆️

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

Impacted Files	Coverage Δ
...apache/pinot/common/helix/ExtraInstanceConfig.java	0.00% <0.00%> (-100.00%)	⬇️
...t/core/plan/StreamingInstanceResponsePlanNode.java	0.00% <0.00%> (-100.00%)	⬇️
...ore/operator/streaming/StreamingResponseUtils.java	0.00% <0.00%> (-100.00%)	⬇️
...ager/realtime/PeerSchemeSplitSegmentCommitter.java	0.00% <0.00%> (-100.00%)	⬇️
...ator/streaming/StreamingSelectionOnlyOperator.java	0.00% <0.00%> (-90.00%)	⬇️
...he/pinot/core/plan/StreamingSelectionPlanNode.java	0.00% <0.00%> (-88.89%)	⬇️
...che/pinot/common/auth/StaticTokenAuthProvider.java	0.00% <0.00%> (-87.50%)	⬇️
...roker/requesthandler/GrpcBrokerRequestHandler.java	0.00% <0.00%> (-87.24%)	⬇️
...re/query/reduce/SelectionOnlyStreamingReducer.java	0.00% <0.00%> (-80.96%)	⬇️
...ller/api/access/BasicAuthAccessControlFactory.java	0.00% <0.00%> (-80.00%)	⬇️
... and 222 more

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