ignite-client-handler tests fail due to hardcoded handshake response size

The following tests fail if you change IgniteProductVersion.CURRENT_VERSION so that the string length is different, because handshake response size changes:

• org.apache.ignite.client.handler.ItClientHandlerMetricsTest#testBytesSentReceived
• org.apache.ignite.client.handler.ItClientHandlerTest#testHandshakeWithAuthenticationValidCredentials
• org.apache.ignite.client.handler.ItClientHandlerTest#testHandshakeValidReturnsSuccess