Refactor Native REPL code to avoid using wide scope VS Code namespace

[anthonykim1]

Native REPL currently directly calls VS Code API such as window.showNotebookDocument.
We should put wrap these methods such as in src/client/common/vscodeApis/windowApis.ts
so that more tests can be easily created.

[anthonykim1]

From feedback #24148 (comment)
also many instances where I can refactor and avoid using workspace directly from VS Code.