Issue with numerical properties using Avatica JDBC driver

### Affected Version

Druid 0.21.1
Avatica 1.18.0

### Description

When I send a query via JDBC driver with a numerical property (eg. numParallelCombineThreads), I get a ClassCastException.

This is an example of how I send the query with context property :
```
val properties = new Properties()
properties.setProperty("numParallelCombineThreads", "4")
val connection = DriverManager.getConnection(url, properties)
val statement = connection.createStatement()
val resultSet = statement.executeQuery(query)
```
and the response I get
```
Exception in thread "main" org.apache.calcite.avatica.AvaticaSqlException: Error -1 (00000) : Error while executing SQL "select caseid from "2a03cee0-2511-4ee2-b2e9-0068527fc437" group by caseid": Remote driver error: RuntimeException: java.util.concurrent.ExecutionException: java.lang.ClassCastException: java.lang.String cannot be cast to java.lang.Integer
```
I also tried with put method, but I get the same error
```
properties.put("numParallelCombineThreads", 4)
```
Requests with string and boolean properties are processed successfully, the problem arise only with numerical values.

Start by reproducing the example with Druid 0.21.1 and Avatica 1.18.0, using a numerical context property through DriverManager and executeQuery. Trace how JDBC connection properties reach query context handling; done means numerical properties work without the reported ClassCastException. The issue names no repository file or test.

Written by the indexing model from the issue text.