### _Why are the changes needed?_
This PR aims to improve out-of-box UX.
Currently, administrators' checking is enforced even when security is disabled, and we are going to deliver the preview of Web UI in 1.8, it may confuse users who use the default configuration to launch Kyuubi sever and explore Kyuubi WebUI (because the user "anonymous" can not visit all users' sessions/engines without being configured as an administrator).
### _How was this patch tested?_
- [ ] Add some test cases that check the changes thoroughly including negative and positive cases if possible
- [ ] Add screenshots for manual tests if appropriate
- [x] [Run test](https://kyuubi.readthedocs.io/en/master/contributing/code/testing.html#running-tests) locally before make a pull request
### _Was this patch authored or co-authored using generative AI tooling?_
No
Closes#5568 from pan3793/admin.
Closes#5568
2eccf659f [Cheng Pan] code dedup and fix test
76f4fd4a3 [Cheng Pan] fix test
d7ca94650 [Cheng Pan] Check administrator only when security is enabled
Authored-by: Cheng Pan <chengpan@apache.org>
Signed-off-by: Cheng Pan <chengpan@apache.org>
9bf234473a