Allow inline sourcemaps for EsBuild

## Problem
According to https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/serverless-sam-cli-using-build-typescript.html, `Sourcemap` can only be set to `true` or `false`.

This is causing issues with devcontainer debug functionality in TypeScript: #3266

If only `Sourcemap` could be set to `inline` or `both` as supported in the documentation, it would solve that issue: https://esbuild.github.io/api/#sourcemap

## Expected behavior
I expect Sourcemap to be able to set to the valid values of the property in Esbuild.

Start by locating the EsBuild configuration that validates or passes the Sourcemap setting, using the issue's linked AWS SAM and Esbuild documentation as context. Support the valid inline and both values, then verify that TypeScript devcontainer debugging can use the resulting sourcemaps.

Written by the indexing model from the issue text.