Enable JDK22 build

[koppor]

Follow-up to #11057 and #11058.

The EA workflow now builds using JDK22 features (using gradle 8.7-rc.3, which supports JDK22 for compilation)

Mandatory checks

• Change in CHANGELOG.md described in a way that is understandable for the average user (if applicable)
• Tests created for changes (if applicable)
• Manually tested changed features in running JabRef (always required)
• Screenshots added in PR description (for UI changes)
• Checked developer's documentation: Is the information available and up to date? If not, I outlined it in this pull request.
• Checked documentation: Is the information available and up to date? If not, I created an issue at https://github.com/JabRef/user-documentation/issues or, even better, I submitted a pull request to the documentation repository.

[koppor]

Blocked by gradle/gradle#16791

tasks.register("generateJournalListMV", JavaExec) {
    group = "JabRef"
    description = "Converts the comma-separated journal abbreviation file to a H2 MVStore"
    classpath = sourceSets.main.runtimeClasspath
    mainClass = "org.jabref.cli.JournalListMvGenerator"
    onlyIf {
        !file("build/resources/main/journals/journal-list.mv").exists()
    }
}

java.lang.UnsupportedClassVersionError: org/jabref/cli/JournalListMvGenerator has been compiled by a more recent version of the Java Runtime (class file version 66.0), this version of the Java Runtime only recognizes class file versions up to 65.0
Successfully started process 'command '/opt/hostedtoolcache/Java_Liberica_jdk/21.0.2-14/x64/bin/java''

[koppor]

For jpackage, we have

Caused by: java.lang.module.InvalidModuleDescriptorException: Unsupported major.minor version 66.0

[koppor]

Should work now. Norma build: JDK21, EA with JDK22

[github-actions]

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