TODO: centralise annotation stripping in FragmentConversionDriver

Per PR 22086 review feedback (expani, mch2): adapters shouldn't be
stripping OperatorAnnotation themselves; the driver should normalise
the tree. Tag the local strip helper as a follow-up so the cleanup
covers every adapter doing this together.

Signed-off-by: Vinay Krishna Pudyodu <vinkrish.neo@gmail.com>

Author: vinaykpud

sandbox/plugins/analytics-backend-datafusion/src/main/java/org/opensearch/be/datafusion/ComparisonTemporalCoercionAdapter.java

@@ -110,6 +110,7 @@ private static RexNode unwrapToTime(RexNode node) {
         return null;
     }
 
+    // TODO: annotation stripping should be centralised in FragmentConversionDriver; revisit alongside the other adapters that strip locally.
     private static RexNode stripAnnotation(RexNode node) {
         while (node instanceof OperatorAnnotation annotation && annotation.unwrap() != null) {
             node = annotation.unwrap();