[DOCS] Update ingest pipeline screenshots for new EUI theme (#75744)

docs/reference/ingest/common-log-format-example.asciidoc

@@ -39,7 +39,7 @@ image::images/ingest/ingest-pipeline-list.png[Kibana's Ingest Node Pipelines lis
 +
 [source,grok]
 ----
-%{IPORHOST:source.ip} %{USER:user.id} %{USER:user.name} \[%{HTTPDATE:@timestamp}\] "%{WORD:http.request.method} %{DATA:url.original} HTTP/%{NUMBER:http.version}" %{NUMBER:http.response.status_code:int} (?:-|%{NUMBER:http.response.body.bytes:int}) %{QS:http.request.referrer} %{QS:user_agent}
+%{IPORHOST:source.ip} %{USER:user.id} %{USER:user.name} \\[%{HTTPDATE:@timestamp}\\] \"%{WORD:http.request.method} %{DATA:url.original} HTTP/%{NUMBER:http.version}\" %{NUMBER:http.response.status_code:int} (?:-|%{NUMBER:http.response.body.bytes:int}) %{QS:http.request.referrer} %{QS:user_agent}
 ----
 // NOTCONSOLE
 +