Minor fix in dynamic template validation (elastic#66166)

As part of elastic#66156 the validation of dynamic templates has been adapted to support runtime fields. As part of that change, a `break` was forgotten, which causes needless additional validation rounds after a template has been already successfully validated against one of the field types.

Author: javanna

server/src/main/java/org/elasticsearch/index/mapper/RootObjectMapper.java

@@ -426,6 +426,7 @@ private static void validateDynamicTemplate(Mapper.TypeParser.ParserContext pars
                         (name, mapping) -> typeParser.parse(name, mapping, parserContext).build(new ContentPath(1)));
                 }
                 dynamicTemplateInvalid = false;
+                break;
             } catch(Exception e) {
                 lastError = e;
             }