Enhancement: add a filter to allow Jetpack Search on/off toggling to be hidden or inactive

### Impacted plugin

Jetpack

### What

Add a filter to allow Jetpack Search on/off toggling to be hidden or inactive

### How

VIP have requested that the client is not given control over whether Jetpack Search is active or not, as they would prefer to handle the activation/deactivation of Search. For the time being they plan to hide our wp-admin section completely and remove it from the sidebar.

A better solution would be a filter that deactivates or removes the on/off toggles from `/wp-admin/admin.php?page=jetpack-search`.

Start at the Jetpack Search admin page identified as /wp-admin/admin.php?page=jetpack-search and trace how its on/off toggles are rendered and handled. Add a filter that lets site owners hide or deactivate those controls, then verify that the page respects the filter while still allowing VIP-managed activation or deactivation.

Written by the indexing model from the issue text.