[bugfix] display stderr on command failure

[DerekTBrown]

Repro

If you run the SDK CLI against a broken Typescript file, nothing useful is outputted:

(base) ~/D/C/n/near-sdk-js ❯❯❯ ./lib/cli/cli.js build --verbose ./examples/src/log.ts                                                                                       ✘ 1 
…  awaiting  Building ./examples/src/log.ts contract...
…  awaiting  Typechecking ./examples/src/log.ts with tsc...
[exec] › ℹ  info      Running command: node_modules/.bin/tsc  --skipLibCheck --experimentalDecorators --target es2020 --moduleResolution node ./examples/src/log.ts
[exec] › ✖  error     Error: Command failed: node_modules/.bin/tsc  --skipLibCheck --experimentalDecorators --target es2020 --moduleResolution node ./examples/src/log.ts 

    at ChildProcess.exithandler (node:child_process:398:12)
    at ChildProcess.emit (node:events:527:28)
    at maybeClose (node:internal/child_process:1092:16)
    at Process.ChildProcess._handle.onexit (node:internal/child_process:302:5)

Root Cause

• The promisified childProcess.exec (invoked here) throws an error if the command returns a non-zero code.
• This error contains stdout and stderr information, but this isn't printed to console in the catch block.

Fix

This PR changes the CLI behavior to print stderr and stdout when a command exits with a non-zero exit code. This is useful for debugging and diagnosis. This is done by unifying the try/catch paths somewhat.

[ailisp]

Fix looks reasonable to me. Thanks @DerekTBrown !

[DerekTBrown]

@ailisp I don't have write access to the repo. Can you merge?

[ailisp]

@DerekTBrown Done. Thank you!