JDK discovery mechanism now working as expected

### Affected version

3.2.0

### Bug description

Executing `mvn org.apache.maven.plugins:maven-toolchains-plugin:3.2.0:display-discovered-jdk-toolchains` works, and returns all JDKs installed on my machine, but I don't know how to cinfigure Maven to use Java 8 for project runtime.

This auto discovery mechanism should work without `~/.m2/toolchains.xml` file per [documentation](https://maven.apache.org/plugins/maven-toolchains-plugin/toolchains/jdk-discovery.html).

My goal is to run project with Java 8.

My `pom.xml`:
```xml

4.0.0

org.springframework.boot
spring-boot-starter-parent
2.7.18


com.username.mock
webserver
0.0.1-SNAPSHOT
webserver
Demo project for Spring Boot














1.8



org.springframework.boot
spring-boot-starter-web

org.springframework.boot
spring-boot-starter-test
test

org.springframework.boot
spring-boot-maven-plugin


org.apache.maven.plugins
maven-toolchains-plugin
3.2.0



select-jdk-toolchain


true
8

```

Error I get with `mvn spring-boot:run`:
```
[INFO] Found 5 possible jdks: [/usr/lib/jvm/java-21-openjdk, /usr/lib/jvm/java-11-openjdk, /usr/lib/jvm/java-24-openjdk, /usr/lib/jvm/java-17-openjdk, /usr/lib/jvm/java-8-openjdk]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 0.884 s
[INFO] Finished at: 2025-06-18T13:41:51+02:00
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-toolchains-plugin:3.2.0:select-jdk-toolchain (default) on project webserver: Cannot find matching toolchain definitions for the following toolchain types:{runtime.version=8}
[ERROR] Define the required toolchains in your ~/.m2/toolchains.xml file.
[ERROR] -> [Help 1]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoFailureException
```