Fix internal API usage

[hatzlj]

as of https://platform.jetbrains.com/t/pluginmanagercore-getplugin-is-now-internal/4272 PluginManagerCore.getPlugin is considered internal API, recommending the approach in this PR to determine the plugin version.

[CodeDrivenMitch]

As I read in the thread there are several ways to get the version, the current one being internal now. Seems to plan to introduce something different.

I want to say that continuing to use internal API does not break the build in the future, nor newer intellij versions using the current plugin version. They will only reject new occurrences of internal API usage, let's say, if we make a new class.

It would break if they rename/move the class, but it does not seem that that's the case

So I'm alright with merging this method, but we could also wait until their official solution. There's really no rush, as they won't punish us for keeping it.

[hatzlj]

As I read in the thread there are several ways to get the version, the current one being internal now. Seems to plan to introduce something different.

I want to say that continuing to use internal API does not break the build in the future, nor newer intellij versions using the current plugin version. They will only reject new occurrences of internal API usage, let's say, if we make a new class.

It would break if they rename/move the class, but it does not seem that that's the case

Thats true, my main reason to fix it again was that it broke our "Verify Plugin" step (see https://github.com/AxonFramework/IdeaPlugin/actions/runs/35622065262/job/106407282152) on dependabot PRs every time such a move occurs. But you're right, we don't need to fix it right now.