Fix usage of randomIntBetween() in testWriteBlobWithRetries (#46380)

This commit fixes the usage of randomIntBetween() in the test 
testWriteBlobWithRetries, when the test generates a random array  
of a single byte.

plugins/repository-s3/src/test/java/org/elasticsearch/repositories/s3/S3BlobContainerRetriesTests.java

@@ -206,7 +206,7 @@ public void testWriteBlobWithRetries() throws Exception {
 
                 if (randomBoolean()) {
                     if (randomBoolean()) {
-                        Streams.readFully(exchange.getRequestBody(), new byte[randomIntBetween(1, bytes.length - 1)]);
+                        Streams.readFully(exchange.getRequestBody(), new byte[randomIntBetween(1, Math.max(1, bytes.length - 1))]);
                     } else {
                         Streams.readFully(exchange.getRequestBody());
                         exchange.sendResponseHeaders(randomFrom(HttpStatus.SC_INTERNAL_SERVER_ERROR, HttpStatus.SC_BAD_GATEWAY,