Test: Fix a second case of bad watch creation

There was still a case with a null text that allowed for 0 attachments
to be created. This commit ensures that greater than zero are created
if the text is null. Otherwise, it uses the same logic to create 0 to 3
random attachments.

Closes #31948

Author: hub-cap

x-pack/plugin/watcher/src/test/java/org/elasticsearch/xpack/watcher/notification/slack/message/SlackMessageTests.java

@@ -461,7 +461,6 @@ public void testTemplateParseSelfGenerated() throws Exception {
         assertThat(parsed, equalTo(template));
     }
 
-    @AwaitsFix(bugUrl = "https://github.com/elastic/elasticsearch/issues/31948")
     public void testTemplateRender() throws Exception {
         Settings settings = SlackMessageDefaultsTests.randomSettings();
         SlackMessageDefaults defaults = new SlackMessageDefaults(settings);
@@ -483,7 +482,9 @@ public void testTemplateRender() throws Exception {
             templateBuilder.setText(randomAlphaOfLength(10));
         }
         if (templateBuilder.text == null || randomBoolean()) {
-            int count = randomIntBetween(0, 3);
+            // ensure at least one attachment in the event the text is null
+            int minimumAttachments = templateBuilder.text == null ? 1 : 0;
+            int count = randomIntBetween(minimumAttachments, 3);
             for (int i = 0; i < count; i++) {
                 Attachment.Template.Builder attachmentBuilder = createRandomAttachmentTemplateBuilder();
                 templateBuilder.addAttachments(attachmentBuilder);