Open current working directory action. (#18013)

## Summary of the Pull Request
Added open current directory action.
## References and Relevant Issues
Need to set this:
https://learn.microsoft.com/en-us/windows/terminal/tutorials/new-tab-same-directory

## Detailed Description of the Pull Request / Additional comments

## Validation Steps Performed
- Ensure shell has been configured
- Run "Open current working directory" action in command palette
- File explorer opens the correct directory

## PR Checklist
- [x] Closes #12859
- [ ] Tests added/passed
- [ ] Documentation updated
- If checked, please file a pull request on [our docs
repo](https://github.com/MicrosoftDocs/terminal) and link it here: #xxx
- [ ] Schema updated (if necessary)

doc/cascadia/profiles.schema.json

@@ -423,6 +423,7 @@
         "newWindow",
         "nextTab",
         "openAbout",
+        "openCWD",
         "openNewTabDropdown",
         "openSettings",
         "openSystemMenu",