Inconsistent search behaviour in advanced settings for Telemetry

[marius-dr]

Kibana version: 7.5.0 BC5.

Describe the bug: With telemetry changing disabled from the yml file, when you search in the Advanced Settings for "telemetry" you get blank space. If you search for something that doesn't return a result you get a "No settings found (Clear search)" prompt.

Steps to reproduce:

1. Set telemetry.allowChangingOptInStatus: false in kibana.yml
2. Search for "telemetry" in the advanced settings page.
3. Search for "afasfg" in the advanced settings page.

Expected behavior:
The behaviour of the second one should be used when searching for "telemetry" while telemetry opting UI is disabled.

Screenshots (if relevant):

Related to: #49798
cc @mikecote

[elasticmachine]

Pinging @elastic/kibana-stack-services (Team:Stack Services)

[elasticmachine]

Pinging @elastic/pulse (Team:Pulse)

[elasticmachine]

Pinging @elastic/kibana-core (Team:Core)