chore: update gitignore and remove env.example.txt

- Add sanity-check-backup/ to gitignore
- Add .vscode/ to gitignore
- Remove env.example.txt (credentials should be managed separately)

Author: AniketDev7

.gitignore

@@ -41,6 +41,8 @@ coverage/
 test/utility/dataFiles/
 test/sanity-check/utility/dataFiles/
 report.json
+sanity-check-backup/
+.vscode/
 
 # TypeScript v1 declaration files
 typings/