Remove duplicate changelog entry (facebook#38177)

Summary:
Pull Request resolved: facebook#38177

Closes facebook#36442

Remove duplicated entries for versions 0.68.6 and 0.69.8 in CHANGELOG.md

Changelog:
[Internal] [Changed] - Remove duplicated entries for versions 0.68.6 and 0.69.8 in CHANGELOG.md

Reviewed By: ryancat

Differential Revision: D47208049

fbshipit-source-id: 664ab35018d6eb1ef299c1efe575132ae7f83d9c

CHANGELOG-pre-070.md

@@ -61,14 +61,6 @@ This file contains all changelogs for releases in the 0.60-0.69 range. Please ch
 
 - Mitigation for Samsung TextInput Hangs ([be69c8b5a7](https://github.com/facebook/react-native/commit/be69c8b5a77ae60cced1b2af64e48b90d9955be5) by [@NickGerleman](https://github.com/NickGerleman))
 
-## v0.69.8
-
-### Fixed
-
-#### Android specific
-
-- Mitigation for Samsung TextInput Hangs ([be69c8b5a7](https://github.com/facebook/react-native/commit/be69c8b5a77ae60cced1b2af64e48b90d9955be5) by [@NickGerleman](https://github.com/NickGerleman))
-
 ## v0.69.7
 
 ### Fixed
@@ -393,14 +385,6 @@ This file contains all changelogs for releases in the 0.60-0.69 range. Please ch
 
 - Mitigation for Samsung TextInput Hangs ([be69c8b5a7](https://github.com/facebook/react-native/commit/be69c8b5a77ae60cced1b2af64e48b90d9955be5) by [@NickGerleman](https://github.com/NickGerleman))
 
-## v0.68.6
-
-### Fixed
-
-#### Android specific
-
-- Mitigation for Samsung TextInput Hangs ([be69c8b5a7](https://github.com/facebook/react-native/commit/be69c8b5a77ae60cced1b2af64e48b90d9955be5) by [@NickGerleman](https://github.com/NickGerleman))
-
 ## v0.68.5
 
 ### Fixed