Move kristenTian to emeritus maintainer (#6208)

Signed-off-by: Flyingliuhub <33105471+flyingliuhub@users.noreply.github.com>

.github/CODEOWNERS

@@ -1 +1 @@
-*   @ananzh @kavilla @AMoo-Miki @ashwin-pc @joshuarrrr @abbyhu2000 @zengyan-amazon @kristenTian @zhongnansu @manasvinibs @ZilongX @Flyingliuhub @BSFishy @curq @bandinib-amzn @SuZhou-Joe @ruanyl @BionIT
+*   @ananzh @kavilla @AMoo-Miki @ashwin-pc @joshuarrrr @abbyhu2000 @zengyan-amazon @zhongnansu @manasvinibs @ZilongX @Flyingliuhub @BSFishy @curq @bandinib-amzn @SuZhou-Joe @ruanyl @BionIT

MAINTAINERS.md

@@ -13,7 +13,6 @@ This document contains a list of maintainers in this repo. See [opensearch-proje
 | Josh Romero               | [joshuarrrr](https://github.com/joshuarrrr)         | Amazon      |
 | Abby Hu                   | [abbyhu2000](https://github.com/abbyhu2000)         | Amazon      |
 | Yan Zeng                  | [zengyan-amazon](https://github.com/zengyan-amazon) | Amazon      |
-| Kristen Tian              | [kristenTian](https://github.com/kristenTian)       | Amazon      |
 | Zhongnan Su               | [zhongnansu](https://github.com/zhongnansu)         | Amazon      |
 | Manasvini B Suryanarayana | [manasvinibs](https://github.com/manasvinibs)       | Amazon      |
 | Tao Liu                   | [Flyingliuhub](https://github.com/Flyingliuhub)     | Amazon      |
@@ -33,3 +32,4 @@ This document contains a list of maintainers in this repo. See [opensearch-proje
 | Mihir Soni    | [mihirsoni](https://github.com/mihirsoni)     | Amazon      |
 | Bishoy Boktor | [boktorbb](https://github.com/boktorbb)       | Amazon      |
 | Sean Neumann  | [seanneumann](https://github.com/seanneumann) | Contributor |
+| Kristen Tian  | [kristenTian](https://github.com/kristenTian) | Amazon      |