elastic#196077)

## Summary

The index details page is always updated even when the plugin is
disabled. Using the pluginEnabled conditional to only update when
enabled.

### How to replicate
1. disable uisetting for search indices plugin
2. go to index management and click on a index detail

Expected: see the old index detail page
actual: goes to the new index detail url but does not render the search
detail page (as plugin disabled)

### Checklist

Delete any items that are not applicable to this PR.

- [ ] [Unit or functional
tests](https://www.elastic.co/guide/en/kibana/master/development-tests.html)
were updated or added to match the most common scenarios
- [ ] [Flaky Test
Runner](https://ci-stats.kibana.dev/trigger_flaky_test_runner/1) was
used on any tests changed

(cherry picked from commit efab00b)