use larger payload in AutomaticDecompressionTest (#2065)

Author: sullis

client/src/test/java/org/asynchttpclient/AutomaticDecompressionTest.java

@@ -42,7 +42,7 @@
 
 @ExtendWith(NettyLeakDetectorExtension.class)
 public class AutomaticDecompressionTest {
-    private static final String UNCOMPRESSED_PAYLOAD = "a".repeat(500);
+    private static final String UNCOMPRESSED_PAYLOAD = "a".repeat(50_000);
 
     private static HttpServer HTTP_SERVER;