test: use intellij-ide-starter for e2e tests

[exigow]

Solves CON-3723

(WIP 🚧; works locally)

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Summary by cubic

Switches IntelliJ E2E tests to IntelliJ IDE Starter for a more reliable, CI-friendly setup and removes the old Remote Robot suite. Addresses CON-3723 by aligning tests with 2024.2 and simplifying test bootstrapping.

• Refactors

  • Replaced Remote Robot tests with IDE Starter driver; rewrote Autocomplete test.
  • Removed legacy GUI, InlineEdit, and Onboarding tests.
  • Set IDE to IC 2024.2 and bumped sinceBuild to 242.
  • Dropped runIdeForUiTests and robot server plugin; tests now install the built plugin via path.to.build.plugin.

• Dependencies

  • Upgraded Kotlin to 2.0.0.
  • Switched test framework to IntelliJ Starter + Platform.
  • Removed com.intellij.remoterobot dependencies.
  • Added kodein-di 7.20.2 and kotlinx-coroutines 1.10.1 for tests.