[8.15] [Request][8.15.4 & 8.16.0] Add RN summary about Defend bug fix (backport #6429) (#6432)

* [Request][8.15.4 & 8.16.0] Add RN summary about Defend bug fix  (#6429)

* First draft

* Fixes links

* Update docs/release-notes/8.15.asciidoc

Co-authored-by: Gabriel Landau <[email protected]>

* Update docs/release-notes/8.16.asciidoc

Co-authored-by: Gabriel Landau <[email protected]>

---------

Co-authored-by: Gabriel Landau <[email protected]>
(cherry picked from commit 471a633)

# Conflicts:
#	docs/release-notes/8.16.asciidoc

* removes 8.16 rns

---------

Co-authored-by: Nastasha Solomon <[email protected]>
Co-authored-by: nastasha.solomon <[email protected]>

Author: mergify[bot]

docs/release-notes/8.15.asciidoc

@@ -38,6 +38,7 @@
 * Fixes a bug where {elastic-defend} could fail to properly enrich Windows API events for short-lived processes on older operating systems that didn't natively include this telemetry, such as Windows Server 2019. This could result in dropped or unattributed API events.  
 * Ensures that {elastic-defend} does not emit an empty `memory_region` if it can't enrich a memory region in an API event. After this fix, {elastic-defend} removes these fields.
 * Fixes an {elastic-defend} bug where Windows API events could be dropped if they contained Unicode characters that couldn't be converted to ANSI.
+* Fixes a race condition that could allow an attacker with administrative rights to disable {elastic-defend} on Windows. We would like to acknowledge Sean Moore (@Fr0g) at https://strafecybersecurity.com[strafecybersecurity.com] for their assistance.
 
 [discrete]
 [[release-notes-8.15.3]]