Clarify release note for external pr (#4481)

Author: paulb777

Firebase/DynamicLinks/CHANGELOG.md

@@ -1,6 +1,6 @@
 # v4.0.6
 - [fixed] Fix component startup time. (#4137)
-- [changed] Internal code cleanup. (#4325)
+- [fixed] Fix due to object deallocation on app launch. (#4308)
 
 # v4.0.5
 - [fixed] Removed references to UIWebViewDelegate to comply with App Store Submission warning. (#3722)