Add known issue for APM Server version 8.6 and older with ES 8.15 (#4844) (#4913)

(cherry picked from commit f7156d6)

Co-authored-by: Vishal Raj <[email protected]>

Fix merge conflict

Author: mergify[bot]

docs/en/observability/apm/known-issues.asciidoc

@@ -22,8 +22,6 @@ _Versions: XX.XX.XX, YY.YY.YY, ZZ.ZZ.ZZ_
 ////
 
 [discrete]
-<<<<<<< HEAD
-=======
 == Tail Sampling may not compact / expired TTLs as quickly as desired, causing increased storage usage.
 
 _Elastic Stack versions: All 8.x versions_
@@ -73,7 +71,6 @@ PUT _component_template/metrics-apm.internal@custom
 ----
 
 [discrete]
->>>>>>> ed75d36f (Add APM Server known issue for TBS (#4862))
 == `prefer_ilm` required in component templates to create custom lifecycle policies
 
 _Elastic Stack versions: 8.15.1+_