[TASK] enable enhanced typescript validation

[JoernBerkefeld]

jsconfig.json > compilerOption.checkJs = true OR // @ts-check

AND

.vscode/settings.json > "javascript.validate.enable": true

this should prevent us from writing bad code and potentially fix issues we already have

dependant on:

• https://github.com/DougMidgley/SFMC-SDK/issues/300