[SPARK-59440][SQL] Support the TIME data type in the hll_sketch_agg function

[stevomitric]

What changes were proposed in this pull request?

Add support for the TIME data type to the hll_sketch_agg aggregate. TIME is physically stored as a long (nanoseconds since midnight), so it is hashed into the HllSketch exactly like the existing LongType path. hll_union_agg needs no change: it only ingests already-serialized BINARY sketches, so a sketch built from a TIME column merges through it unchanged.

Why are the changes needed?

Part of SPARK-57550 (extend support for the TIME data type). Approximate distinct counting over TIME columns is a natural, previously-missing capability.

Does this PR introduce any user-facing change?

Yes. hll_sketch_agg(time_col[, lgConfigK]) is now accepted; previously it raised an analysis error for TIME inputs.

How was this patch tested?

New unit test in DatasketchesHllSketchSuite covering analyzer acceptance, cardinality estimation over TIME values, precision-insensitive de-duplication, and a hll_union_agg round-trip over sketches built from a TIME column.

Was this patch authored or co-authored using generative AI tooling?

Co-Authored-By: Claude Opus 4.8

[stevomitric]

cc @uros-b PTAL.

[uros-b]

sql/catalyst/.../aggregate/datasketchesAggregates.scala (inputTypes TypeCollection, ~L118-124) -- Placing AnyTimeType before StringType in the ordered TypeCollection silently changes coercion for TIMESTAMP / TIMESTAMP_NTZ / DATE inputs in the default ANSI configuration. For a TIME input the ordering is irrelevant (it is accepted by the order-independent expectedType.acceptsType short-circuit in implicitCast), but for a type the collection does not directly accept, ANSI implicitCast walks the members in order and takes the first that canANSIStoreAssign permits. canANSIStoreAssign(TimestampType, TimeType(6)) is true via the (_: DatetimeType, _: DatetimeType) arm, and AnyTimeType now precedes StringType, so:

• On master, hll_sketch_agg(ts_col) coerces the timestamp to STRING (AtomicType -> StringType store-assign) and sketches its string form, counting distinct timestamps correctly.
• After this PR, the same call coerces to TIME(6) and sketches only the nanos-of-day (canAnsiCast(TimestampType, TimeType) is true, so the cast executes) -- timestamps that share a wall-clock time-of-day but differ in date collapse to one sketch entry, silently under-counting distinct values. TIMESTAMP_NTZ behaves identically. DATE is also re-routed to a TIME(6) target (store-assign true) but has no DateType -> TimeType cast rule, so it takes an error path instead of its prior working STRING path.