Remove nikunjb@ from //base/metrics/OWNERS

They report that they are no longer on the Chrome team.

Change-Id: Ib08b05ac2770420f5d0347bfd13c876c925fd94d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1994276
Auto-Submit: Reilly Grant <reillyg@chromium.org>
Commit-Queue: Brian White <bcwhite@chromium.org>
Reviewed-by: Brian White <bcwhite@chromium.org>
Cr-Commit-Position: refs/heads/master@{#730231}

base/metrics/OWNERS

@@ -4,7 +4,6 @@ holte@chromium.org
 isherman@chromium.org
 jwd@chromium.org
 mpearson@chromium.org
-nikunjb@chromium.org
 rkaplow@chromium.org
 
 # COMPONENT: Internals>Metrics