Fix observability solution name (#158983)

Not sure if the original text was intentional. 

If APM needs to be more prominent here, you could say *Elastic
Observability and APM* , but it's misleading to say that you can use
Elastic APM for all of the use cases listed here.

Note that I didn't search the Kibana Guide for other instances of this
problem; I just noticed this while doing something else and wanted to
make sure it's fixed.

### Checklist

Delete any items that are not applicable to this PR.

- [x] Any text added follows [EUI's writing
guidelines](https://elastic.github.io/eui/#/guidelines/writing), uses
sentence case text and includes [i18n
support](https://github.com/elastic/kibana/blob/main/packages/kbn-i18n/README.md)

docs/setup/connect-to-elasticsearch.asciidoc

@@ -31,7 +31,7 @@ Discover, extract, and index your web content into App Search engines using the
 Search across Google Drive, GitHub, Salesforce, and many other web services using
 {workplace-search-ref}/workplace-search-content-sources.html[Workplace Search content sources].
 
-* *Elastic APM.*
+* *Elastic Observability.*
 Get logs, metrics, traces, and uptime data into the Elastic Stack.
 Integrations are available for popular services and platforms,
 such as Nginx, AWS, and MongoDB,