feat: enable max/min udaf for string & bytes data types

- The max and min udaf was generalized to handle date & time data types
  See - 5134393
- As a result, the code was capable of supporting string and bytes data types
- This commit simply enables them in the max and min udaf's

ksqldb-engine/src/main/java/io/confluent/ksql/function/udaf/max/MaxAggFunctionFactory.java

@@ -52,6 +52,8 @@ public KsqlAggregateFunction createAggregateFunction(
       case DATE:
       case TIME:
       case TIMESTAMP:
+      case STRING:
+      case BYTES:
         return new MaxKudaf(FUNCTION_NAME, initArgs.udafIndex(), argSchema);
       default:
         throw new KsqlException(

ksqldb-engine/src/main/java/io/confluent/ksql/function/udaf/min/MinAggFunctionFactory.java

@@ -51,6 +51,8 @@ public KsqlAggregateFunction createAggregateFunction(
       case DATE:
       case TIME:
       case TIMESTAMP:
+      case STRING:
+      case BYTES:
         return new MinKudaf(FUNCTION_NAME, initArgs.udafIndex(), argSchema);
       default:
         throw new KsqlException(