[BUG] Fix misleading "cannot run on GPU" warnings when AQE is enabled

[andygrove]

Describe the bug

With AQE enabled, the query plan gets optimized multiple times by the plugin, and once the plan contains query stages that have already been executed, we see the following warnings. This doesn't cause any incorrect behavior but is misleading since these query stages likely already executed on the GPU.

!NOT_FOUND <ShuffleQueryStageExec> cannot run on GPU because no GPU enabled version of operator class org.apache.spark.sql.execution.adaptive.ShuffleQueryStageExec could be found
!NOT_FOUND <BroadcastQueryStageExec> cannot run on GPU because no GPU enabled version of operator class org.apache.spark.sql.execution.adaptive.BroadcastQueryStageExec could be found
!NOT_FOUND <AdaptiveSparkPlanExec> cannot run on GPU because no GPU enabled version of operator class org.apache.spark.sql.execution.adaptive.AdaptiveSparkPlanExec could be found

Steps/Code to reproduce bug
Execute any query containing broadcast or shuffle exchanges with AQE enabled.

Expected behavior
We should not see these warnings.

Environment details (please complete the following information)
NA

Additional context
N/A