Remove release notes for missing PR !! (elastic#199878)

## Summary

This PR elastic#196109 was never
back-ported to 8.16.0 !!

(cherry picked from commit 90b14e2)

docs/CHANGELOG.asciidoc

@@ -154,7 +154,6 @@ Discover::
 * Adds density settings to allow further customization of the Documents table layout ({kibana-pull}188495[#188495]).
 * Enables the time picker for indices without the @timestamp field when editing ES|QL queries ({kibana-pull}184361[#184361]).
 Elastic Observability solution::
-* Show monitors from all permitted spaces !! ({kibana-pull}196109[#196109]).
 * Adds experimental logs overview to the observability hosts and service overviews ({kibana-pull}195673[#195673]).
 * Show alerts for entities ({kibana-pull}195250[#195250]).
 * Create sub-feature role to manage APM settings write permissions ({kibana-pull}194419[#194419]).