Fix invalid path in CODEOWNERS (#24839)

* Fix invalid path in CODEOWNERS

* Apply suggestions from code review

.github/CODEOWNERS

@@ -4,7 +4,6 @@
 /global.json                    @aspnet/build
 /.azure/                        @aspnet/build
 /.config/                       @aspnet/build
-/build/                         @aspnet/build
 /eng/                           @aspnet/build
 /eng/common/                    @dotnet-maestro-bot
 /eng/Versions.props             @dotnet-maestro-bot @dougbu