Update CHANGES.md with Python prism note. (#33263)

Release branch equivalent to #33262 which updates the blog as well.

The note has already been added to the github release blurb: https://github.com/apache/beam/releases/tag/v2.61.0

Back updating the CHANGES for something that made the 2.61 release, but wasn't noted in the CHANGES

CHANGES.md

@@ -77,9 +77,10 @@
 
 * Added support for read with metadata in MqttIO (Java) ([#32195](https://github.com/apache/beam/issues/32195))
 * X feature added (Java/Python) ([#X](https://github.com/apache/beam/issues/X)).
-* Added support for processing events which use a global sequence to "ordered" extension (Java) [#32540](https://github.com/apache/beam/pull/32540)
+* Added support for processing events which use a global sequence to "ordered" extension (Java) ([#32540](https://github.com/apache/beam/pull/32540))
 * Add new meta-transform FlattenWith and Tee that allow one to introduce branching
   without breaking the linear/chaining style of pipeline construction.
+* Use Prism as a fallback to the Python Portable runner when running a pipeline with the Python Direct runner ([#32876](https://github.com/apache/beam/pull/32876))
 
 ## Breaking Changes