SAM: debug typescript lambda locally

## Problem
When I use esbuild to create a SAM application in typescript, I'm unable to set breakpoints in my typescript code using the direct-invoke vscode debug target.

I receive the following error:

```
Debugger attached.
Could not read source map for file:///var/task/app.js: ENOENT: no such file or directory, open 'd:\Matt\Documents\coding-projects\algoa-gtfs\generate-gtfs\app.js.map'
2023-03-04T19:23:29.832Z 35b556c5-afc6-4038-9b97-ab49edea2f37 INFO hello world
END RequestId: 35b556c5-afc6-4038-9b97-ab49edea2f37
REPORT RequestId: 35b556c5-afc6-4038-9b97-ab49edea2f37 Init Duration: 0.09 ms Duration: 105546.28 ms Billed Duration: 105547 ms Memory Size: 128 MB Max Memory Used: 128 MB
null
```

This doesn't make sense because the source map is at `D:\Matt\Documents\coding-projects\algoa-gtfs\.aws-sam\build\AlgoaGtfsFunction\app.js.map`

## Steps to reproduce the issue
1. Download this commit: https://github.com/mattsains/algoa-gtfs/tree/218f0bfb7cf33302c5bd0b7f0df7bf97aa7fd80b
1. Open in vscode
2. set a breakpoint in `app.ts`
3. Run `sam build`
4. Hit F5

## Expected behavior
The debugger should load source maps from `D:\Matt\Documents\coding-projects\algoa-gtfs\.aws-sam\build\AlgoaGtfsFunction\app.js.map` and the lambda should break at the break point set.

## System details (run the `AWS: About Toolkit` command)
OS: Windows_NT x64 10.0.22621
Visual Studio Code extension host: 1.76.0
AWS Toolkit: 1.63.0
node: 16.14.2
electron: 19.1.11

Reproduce the direct-invoke VS Code debug flow using the linked commit, app.ts, and the generated .aws-sam/build/AlgoaGtfsFunction/app.js.map. Start by tracing how the direct-invoke target resolves the app.js source map, then verify that breakpoints in app.ts resolve and pause in the local Lambda.

Written by the indexing model from the issue text.