Make Watcher validation message copy/pasteable

Watcher validates `action.auto_create_index` upon startup. If a user
specifies a pattern that does not contain watcher indices, it raises an
error message to include a list of three indices. However, the indices
are separated by a comma and a space which is not considered in parsing.

With this commit we change the error message string so it does not
contain the additional space thus making it more straightforward to copy
it to the configuration file.

Closes elastic#33369

x-pack/plugin/watcher/src/main/java/org/elasticsearch/xpack/watcher/Watcher.java

@@ -535,7 +535,7 @@ static void validAutoCreateIndex(Settings settings, Logger logger) {
 
         String errorMessage = LoggerMessageFormat.format("the [action.auto_create_index] setting value [{}] is too" +
                 " restrictive. disable [action.auto_create_index] or set it to " +
-                "[{}, {}, {}*]", (Object) value, Watch.INDEX, TriggeredWatchStoreField.INDEX_NAME, HistoryStoreField.INDEX_PREFIX);
+                "[{},{},{}*]", (Object) value, Watch.INDEX, TriggeredWatchStoreField.INDEX_NAME, HistoryStoreField.INDEX_PREFIX);
         if (Booleans.isFalse(value)) {
             throw new IllegalArgumentException(errorMessage);
         }

x-pack/plugin/watcher/src/test/java/org/elasticsearch/xpack/watcher/WatcherPluginTests.java

@@ -37,7 +37,7 @@ public void testValidAutoCreateIndex() {
 
         IllegalArgumentException exception = expectThrows(IllegalArgumentException.class,
                 () -> Watcher.validAutoCreateIndex(Settings.builder().put("action.auto_create_index", false).build(), logger));
-        assertThat(exception.getMessage(), containsString("[.watches, .triggered_watches, .watcher-history-*]"));
+        assertThat(exception.getMessage(), containsString("[.watches,.triggered_watches,.watcher-history-*]"));
 
         Watcher.validAutoCreateIndex(Settings.builder().put("action.auto_create_index",
                 ".watches,.triggered_watches,.watcher-history*").build(), logger);
@@ -46,16 +46,16 @@ public void testValidAutoCreateIndex() {
 
         exception = expectThrows(IllegalArgumentException.class,
                 () -> Watcher.validAutoCreateIndex(Settings.builder().put("action.auto_create_index", ".watches").build(), logger));
-        assertThat(exception.getMessage(), containsString("[.watches, .triggered_watches, .watcher-history-*]"));
+        assertThat(exception.getMessage(), containsString("[.watches,.triggered_watches,.watcher-history-*]"));
 
         exception = expectThrows(IllegalArgumentException.class,
                 () -> Watcher.validAutoCreateIndex(Settings.builder().put("action.auto_create_index", ".triggered_watch").build(), logger));
-        assertThat(exception.getMessage(), containsString("[.watches, .triggered_watches, .watcher-history-*]"));
+        assertThat(exception.getMessage(), containsString("[.watches,.triggered_watches,.watcher-history-*]"));
 
         exception = expectThrows(IllegalArgumentException.class,
                 () -> Watcher.validAutoCreateIndex(Settings.builder().put("action.auto_create_index", ".watcher-history-*").build(),
                         logger));
-        assertThat(exception.getMessage(), containsString("[.watches, .triggered_watches, .watcher-history-*]"));
+        assertThat(exception.getMessage(), containsString("[.watches,.triggered_watches,.watcher-history-*]"));
     }
 
     public void testWatcherDisabledTests() throws Exception {