feat(js): Add live: 'rejectOnError' execution mode to execute method

[Lms24]

The Sentry CLI JS interface's execute method takes a live parameter as a second argument:

• if false, stdio is returned and the promise returned from execute rejects/resolves based on the CLI binary's exit code.
• if true, CLI stdio is piped to the process calling execute, but the returned promise always resolves regardless of the exit code (raised in Exit code ignored with SentryCli.execute([...], true) (live mode) #2062)

This PR adds a third value ('rejectOnError') to live, which still pipes stdio but also rejects if the CLI binary's exit code was non-zero. Arguably, this is what true should do but to avoid a breaking change for now, let's introduce this as a new value instead.

This PR also makes a second small change, which is to allow the Releases.uploadSourceMaps method to forward a live option to its .execute call. This is necessary because at the moment, uploadSourceMaps always calls .execute with live: true but in case of the bundler plugins, we want to use the new live: 'rejectOnError' mode.

Also added a couple of unit tests

closes #2062
ref getsentry/sentry-javascript-bundler-plugins#670

[szokeasaurusrex]

Looks good, see comments prior to merge

[szokeasaurusrex]

Also perhaps would be good for someone more well-versed in JS to also take a glance at this before we merge

[chargome]

LGTM