Fixes #39752 - Remove leapp preupgrade report from legacy implementation in the leapp plugin

[kmalyjur]

Removed webpack/components/PreupgradeReports, webpack/components/PreupgradeReportsList and all related files.

CANNOT BE MERGED YET, #183 is blocking it.

[MariaAga]

AI findings of a few remaining files that can be deleted:

• webpack/csrf.js — sole consumer was the deleted PreupgradeReports/index.js. Zero references left.
• (not a 100% sure a bout this one, please check before deleting)
  The whole non-API controller stack: app/controllers/preupgrade_reports_controller.rb, resources :preupgrade_reports, only: %i[index] (config/routes.rb:4), app/views/preupgrade_reports/{index,show}.json.rabl, app/views/preupgrade_report_entries/base.json.rabl, test/functional/preupgrade_reports_controller_test.rb.
  Only caller was preupgrade_reports_path(...) in the deleted partial. If dropped, also remove :preupgrade_reports => %i[index show job_invocation] from engine.rb:27 (it already listed show/job_invocation, which that controller never had).
• jest.config.js SVG transform + the jest-svg-transformer devDependency — the only .svg imports lived in the deleted PreupgradeReportsList/components/helpers.js; none remain.

[kmalyjur]

@MariaAga thank you, I deleted the files you mentioned except for the API controllers, because they are still used by PreupgradeReportsTable.

[Lukshio]

@kmalyjur Bugs are merged so this PR is unblocked. Please rebase

[Lukshio]

Packit tested, #183 is merged