failing test: target=code: typescript

## Problem
The following test is failing in CI (and probably locally as well):

```
SamDebugConfigurationProvider
makeConfig
target=code: typescript:
Error: TypeScript compiler "tsc" not found in node_modules/ or the system.
at compileTypeScript (src/shared/sam/debugger/typescriptSamDebug.ts:214:15)
at async Object.makeTypescriptConfig (src/shared/sam/debugger/typescriptSamDebug.ts:77:5)
at async SamDebugConfigProvider.makeConfig (src/shared/sam/debugger/awsSamDebugger.ts:635:32)
at async Context. (src/test/shared/sam/debugger/samDebugConfigProvider.test.ts:706:29)
```

According to PR's it looks like it started failing yesterday

Start with src/test/shared/sam/debugger/samDebugConfigProvider.test.ts at the target=code: typescript case, then read compileTypeScript in src/shared/sam/debugger/typescriptSamDebug.ts and its call from awsSamDebugger.ts. Run the failing test and determine why tsc is unavailable; done means this CI test passes without the reported compiler-not-found error.

Written by the indexing model from the issue text.