[java][retrofit2] Fix: Always set jakarta_annotation_version

Created by: edwardmp

Commit 1735ab9d added changes to set the jakarta_annotation_version.

I've recently noticed that when using retrofit2 library, the project builds fine with Maven but fails with Gradle.

The build fails due to Could not get unknown property 'jakarta_annotation_version' for object of type org.gradle.api.internal.artifacts.dsl.dependencies.DefaultDependencyHandler.

Digging into this, in the generated build.gradle the jakarta_annotation_version is never set. Upon closer inspection, aforementioned commit seems to indeed set it differently for the Maven build configuration than the Gradle build configuration (same for SBT configuration) for that matter.

The issue is that due to human error the jakarta_annotation_version line is added within the {{#usePlayWS}} block, meaning it won't be generated when usePlayWS is false, even though it should.

This commit changes this to always generate it.

E.g. before applying this commit build.gradle looks like:

ext {
    oltu_version = "1.0.1"
    retrofit_version = "2.3.0"
    swagger_annotations_version = "1.5.22"
    junit_version = "4.13.2"
    json_fire_version = "1.8.0"
}

After applying the change:

ext {
    oltu_version = "1.0.1"
    retrofit_version = "2.3.0"
    jakarta_annotation_version = "1.3.5"
    swagger_annotations_version = "1.5.22"
    junit_version = "4.13.2"
    json_fire_version = "1.8.0"
}   

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