Fix SingleTimeMonotonic to take into account FlatMap's TableFunc's preserves_monotonicity

Author: ggevay

src/compute-types/src/plan/interpret/physically_monotonic.rs

@@ -139,12 +139,10 @@ impl Interpreter for SingleTimeMonotonic<'_> {
         _input_key: &Option<Vec<MirScalarExpr>>,
         input: Self::Domain,
         _exprs: &Vec<MirScalarExpr>,
-        _func: &TableFunc,
+        func: &TableFunc,
         _mfp: &MapFilterProject,
     ) -> Self::Domain {
-        // In a single-time context, we just propagate the monotonicity
-        // status of the input
-        input
+        PhysicallyMonotonic(input.0 && func.preserves_monotonicity())
     }
 
     fn join(

test/sqllogictest/transform/relax_must_consolidate.slt

@@ -1229,6 +1229,7 @@ Explained Query:
       Reduce::Hierarchical
         aggr_funcs=[max]
         monotonic
+        must_consolidate
         key_plan
           project=()
         val_plan=id