Spark Connector GRPC reader fix for reading realtime tables

[cbalci]

Change
Previously the GRPC reader in Spark Connector plugin was only able to send OFFLINE table queries. This PR fixes that and enables the connector to issue both OFFLINE and REALTIME queries based on the table type.

Testing

• Integration tests in ExampleSparkPinotConnectorTest are updated accordingly.

bugfix

[codecov-commenter]

Codecov Report

Merging #8824 (0a1e982) into master (8b2b8f5) will decrease coverage by 5.33%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master    #8824      +/-   ##
============================================
- Coverage     68.15%   62.82%   -5.34%     
- Complexity     4626     4641      +15     
============================================
  Files          1735     1695      -40     
  Lines         91298    89486    -1812     
  Branches      13636    13453     -183     
============================================
- Hits          62226    56218    -6008     
- Misses        24733    29223    +4490     
+ Partials       4339     4045     -294     

Flag	Coverage Δ
integration2	?
unittests1	66.19% <ø> (-0.04%)	⬇️
unittests2	14.10% <ø> (-0.06%)	⬇️

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Impacted Files	Coverage Δ
...va/org/apache/pinot/core/routing/RoutingTable.java	0.00% <0.00%> (-100.00%)	⬇️
...va/org/apache/pinot/common/config/NettyConfig.java	0.00% <0.00%> (-100.00%)	⬇️
...a/org/apache/pinot/common/metrics/MinionMeter.java	0.00% <0.00%> (-100.00%)	⬇️
...g/apache/pinot/common/metrics/ControllerMeter.java	0.00% <0.00%> (-100.00%)	⬇️
.../apache/pinot/common/metrics/BrokerQueryPhase.java	0.00% <0.00%> (-100.00%)	⬇️
.../apache/pinot/common/metrics/MinionQueryPhase.java	0.00% <0.00%> (-100.00%)	⬇️
...apache/pinot/common/helix/ExtraInstanceConfig.java	0.00% <0.00%> (-100.00%)	⬇️
...ache/pinot/server/access/AccessControlFactory.java	0.00% <0.00%> (-100.00%)	⬇️
...he/pinot/common/messages/SegmentReloadMessage.java	0.00% <0.00%> (-100.00%)	⬇️
...he/pinot/common/messages/TableDeletionMessage.java	0.00% <0.00%> (-100.00%)	⬇️
... and 371 more

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