Update changelog for version 1.7.0

Remove "Unreleased" section

Author: aeisenberg

extensions/ql-vscode/CHANGELOG.md

@@ -1,7 +1,5 @@
 # CodeQL for Visual Studio Code: Changelog
 
-## [UNRELEASED]
-
 ## 1.7.0 - 20 December 2024
 
 - Add a palette command that allows importing all databases directly inside of a parent folder. [#3797](https://github.com/github/vscode-codeql/pull/3797)