ExtensionLoader.getActivateExtension 一个小的优化

[sin-ning]

• I have searched the issues of this repository and believe that this is not a duplicate.
• [ -] I have checked the FAQ of this repository and believe that this is not a duplicate.

Environment

• Dubbo version: 2.7.3

ExtensionLoader.getActivateExtension

                if (isMatchGroup(group, activateGroup)) {
                    // 这个应该放到 if 里面，会更合适
                    T ext = getExtension(name);
                    if (!names.contains(name)
                            && !names.contains(Constants.REMOVE_VALUE_PREFIX + name)
                            && isActive(activateValue, url)) {
                        exts.add(ext);
                    }

[cvictory]

Can you optimize the code and post pull request?