changelog: Add 9.0.4 release notes (#17586)

* changelog: Add 9.0.4 release notes

* Remove no-op fix in 9.0.3

Author: carsonip

docs/release-notes/index.md

@@ -30,7 +30,14 @@ _No new features or enhancements_
 
 ### Fixes [9-1-0-fixes]
 
-_No new fixes_ 
+_No new fixes_
+
+## 9.0.4 [elastic-apm-9.0.4-release-notes]
+
+### Fixes [elastic-apm-9.0.4-fixes]
+
+* Tail-based sampling: Fix missing or infrequent monitoring metric `lsm_size` and `value_log_size` ([#17512](https://github.com/elastic/apm-server/pull/17512))
+* Fix default tracer `http request sent to https endpoint` error when both self-instrumentation and TLS are enabled ([#17293](https://github.com/elastic/apm-server/pull/17293))
 
 ## 9.0.3 [elastic-apm-9.0.3-release-notes]
 
@@ -43,7 +50,6 @@ _No new fixes_
 * Tail-based sampling: Fix ever-increasing dynamic group count monitoring metric ([#17042](https://github.com/elastic/apm-server/pull/17042))
 * Tail-based sampling: Fix incorrectly large pebble database `lsm_size` monitoring metric in edge cases which causes TBS to be bypassed ([#17149](https://github.com/elastic/apm-server/pull/17149))
 * Tail-based sampling: Log pubsub errors at error or warn level ([#17135](https://github.com/elastic/apm-server/pull/17135))
-* Tail-based sampling: Fix infrequent storage monitoring metric ([#17154](https://github.com/elastic/apm-server/pull/17154))
 
 ## 9.0.2 [elastic-apm-9.0.2-release-notes]