Fix to propagate `ServiceRequestContext` to `ServerErrorHandler`

[ikhoon]

Motivation:

An event loop of the Channel of a request is used to subscribe to a returned HttpResponse. https://github.com/line/armeria/blob/3112b50cb6d2bd0cd31bac17796c5e6a01cc347c/core/src/main/java/com/linecorp/armeria/server/HttpServerHandler.java#L453-L457 The channel event loop is not a context-aware event loop, so ServiceRequestContext is not available in the thread local. As a result, request-scoped MDC won't work.

Modifications:

• Push ServiceRequestContext before calling ServerErrorHandler.onServiceException()

Result:

ServiceRequestContext is now correctly propagated to ServerErrorHandler.

[github-actions[bot]]

🔍 Build Scan® (commit: 059d61b4479d53d707f2bd5c5298c6edb7470f86)

Job name	Status	Build Scan®
build-windows-latest-jdk-21	✅	https://ge.armeria.dev/s/ssuqu3igg542e
build-self-hosted-unsafe-jdk-8	✅	https://ge.armeria.dev/s/lh2kisl6iui7y
build-self-hosted-unsafe-jdk-21-snapshot-blockhound	✅	https://ge.armeria.dev/s/6g6nhmxhosflm
build-self-hosted-unsafe-jdk-17-min-java-17-coverage	✅	https://ge.armeria.dev/s/i2mcwanzofxrc
build-self-hosted-unsafe-jdk-17-min-java-11	✅	https://ge.armeria.dev/s/4r5gecbhmrife
build-self-hosted-unsafe-jdk-17-leak	✅	https://ge.armeria.dev/s/ifkshdfq43x7c
build-self-hosted-unsafe-jdk-11	✅	https://ge.armeria.dev/s/yepjgufka6sw4
build-macos-12-jdk-21	✅	https://ge.armeria.dev/s/ozw3imofmdhoe

[minwoox]

@ikhoon 👍 👍 👍