[Monitor] harden async try/catch

[markwolff]

No description provided.

[xirzec]

This PR looks great but can we wait until after #12417 goes in so we don't accidentally lose the changes?

[xirzec]

Changes look good, just a couple comments.

[xirzec]

do we have an alias for what statusCode: 0 means?

[markwolff]

Added StatusCode.Undefined to Constants. The ingestion server will never return this code and so I don't think it makes sense to move it to codegen, but it feels awkward having a one-off alias here. WDYT?

[xirzec]

I mean how is this code going to be documented so that the user can figure out what it means? Is there a different StatusCode that makes sense here?

[markwolff]

This status code is just meant to be a non-retriable error, but I'm not sure if another HTTP code make sense here. An OTel code could be used, but they are (were) grpc based, so they don't map well. Alternatively, I can just rethrow here and let the caller handle it

[xirzec]

Ohhhh it's an HTTP status code. I'm OK with 0 for this, other runtimes have used that for weird internal errors.

[xirzec]

Some CI failues:

FAILURE (1)
================================
@microsoft/opentelemetry-exporter-azure-monitor (13.93 seconds)
An invalid connection string was passed in. There may be telemetry loss instrumentationkey=foo-ikey
[@microsoft/opentelemetry-exporter-azure-monitor] Returned error code: 1
An invalid connection string was passed in. There may be telemetry loss instrumentationkey=foo-ikey
An invalid connection string was passed in. There may be telemetry loss instrumentationkey=foo-ikey
An invalid connection string was passed in. There may be telemetry loss instrumentationkey=foo-ikey
An invalid connection string was passed in. There may be telemetry loss instrumentationkey=foo-ikey
An invalid connection string was passed in. There may be telemetry loss instrumentationkey=foo-ikey
{ [Error: ENOENT: no such file or directory, scandir 'C:\Users\VSSADM~1\AppData\Local\Temp\ot-azure-exporter-abc']
  errno: -4058,
  code: 'ENOENT',
  syscall: 'scandir',
  path:
   'C:\\Users\\VSSADM~1\\AppData\\Local\\Temp\\ot-azure-exporter-abc' }
{ [Error: ENOENT: no such file or directory, scandir 'C:\Users\VSSADM~1\AppData\Local\Temp\ot-azure-exporter-abc']
  errno: -4058,
  code: 'ENOENT',
  syscall: 'scandir',
  path:
   'C:\\Users\\VSSADM~1\\AppData\\Local\\Temp\\ot-azure-exporter-abc' }
================================

[jmealo]

@xirzec: Could we get these fixes tagged in a release on NPM? Thanks!