Fixes #39273 - removed showHide prop and its functionality, since it is not used anymore

[andreilakatos]

Remove the obsolete showHide prop and any logic that depended on it from the Foreman template Editor UI. The prop was never supplied from Rails (react_component('Editor', …) in templates/_form.html.erb only passes showImport, showPreview, and showHostSelector), so this is dead-code cleanup with no change to server-rendered props.

Changes

Drop showHide from the Editor component tree (props, conditionals, and defaults as applicable).
Update Editor unit tests and Jest snapshots so they no longer reference showHide.
No changes to provisioning templates, renderer_test, or snapshot content for redhat_register—this is React-only.
How to test

Prerequisites

Foreman dev environment with Node deps installed, or CI that runs the JS test suite.

Steps

Review the diff and confirm only showHide (and related wiring) was removed—not showPreview / showHostSelector / showImport.
Open Hosts → Provisioning Templates (or another screen that uses the same Editor), edit a template, and confirm Editor / Preview / Changes tabs and the toolbar still behave normally.
Run the Editor tests, for example:
npm test -- webpack/assets/javascripts/react_app/components/Editor
(or the subset of tests/snapshots your branch touches, e.g. Editor.test.js, EditorNavbar.test.js, EditorOptions.test.js, integration.test.js).

[Lukshio]

Hi, this is straightforward PR, changes looks good.

[Lukshio]

Manually tested

[adamruzicka]

Pro-forma ACK, the real ACK(s) are in the comments.

[adamruzicka]

Thank you @andreilakatos & @Lukshio !