Context start is logged twice for ee10

**Jetty-12.0**

**Jetty Environment**
ee10

Whenever an ee10 webapp starts, the start is logged twice, once by `ContextHandler` and once by `ServletContextHandler`. Running from the distro we see:

>
> 2024-05-14 02:13:37.517:INFO :oejsh.ContextHandler:main: Started oeje10w.WebAppContext@3724b43e{root,/,b=file:///home/janb/src/jetty-eclipse/jetty-12.0.x/jetty-home/target/base/webapps/root/,a=AVAILABLE,h=oeje10s.SessionHandler@2e807c54{STARTED}}{/home/janb/src/jetty-eclipse/jetty-12.0.x/jetty-home/target/base/webapps/root}
> 2024-05-14 02:13:37.518:INFO :oejes.ServletContextHandler:main: Started oeje10w.WebAppContext@3724b43e{root,/,b=file:///home/janb/src/jetty-eclipse/jetty-12.0.x/jetty-home/target/base/webapps/root/,a=AVAILABLE,h=oeje10s.SessionHandler@2e807c54{STARTED}}{/home/janb/src/jetty-eclipse/jetty-12.0.x/jetty-home/target/base/webapps/root}
>

Might be best to just log once.

Reproduce the duplicate startup messages with an ee10 webapp from the Jetty 12.0 distribution, then inspect the startup logging in ContextHandler and ServletContextHandler. Determine which shared or overlapping path emits each message; done means an ee10 context start produces one startup log entry instead of two.

Written by the indexing model from the issue text.