Describe the bug

When trying to use OIDC extension Dev UI with keycloak disabled, and targeting for example EntraID, through an HTTP Proxy, it won't work (but token validation inside the application is OK) :
Dev UI won't be able to access OIDC metadata URL because it does not take quarkus.oidc.proxy.* properties into account (nor JVM http.Proxy, ... system properties), we get a timeout while accessing oidc metadata.

The cause seems to be that the Vert.x WebClient used by OIDC dev UI does not use proxy configuration if present (see OidcDevServicesUtils createWebClient method).

Expected behavior

OIDC Dev UI should use proxy Configuration

Actual behavior

OIDC Dev UI fails to access OIDC endpoints even if quarkus.oidc.proxy.* properties are set up.

How to Reproduce?

Follow https://quarkus.io/guides/security-openid-connect-providers#microsoft to set up a quarkus application, and add quarkus.oidc.proxy.* to make OIDC mechanism access endpoints through a proxy.
The OIDC extension will take proxy conf into account, but Dev UI won't.

Output of uname -a or ver

4.18.0-553.64.1.el8_10.x86_64 #1 SMP Wed Jul 23 16:42:14 EDT 2025 x86_64 x86_64 x86_64 GNU/Linux

Output of java -version

openjdk version "18.0.2.1" 2022-08-18 OpenJDK Runtime Environment (build 18.0.2.1+1-1) OpenJDK 64-Bit Server VM (build 18.0.2.1+1-1, mixed mode, sharing)

Quarkus version or git rev

3.20.2

Build tool (ie. output of mvnw --version or gradlew --version)

Maven 3.9.11

Additional information

No response