Skip and log warning when lambda_metric called with invalid name or value

[nhulston]

What does this PR do?

When lambda_metric is called with an invalid name or value, we skip the metric and log a warning. This ensures that if multiple metrics are sent in one lambda invocation and only one is invalid, the rest still get delivered.

Motivation

#347

Testing Guidelines

Unit tests

Manual testing; I have a lambda with this handler:

from datadog_lambda.metric import lambda_metric

def main(event, context):
    print('Sending metric...')

    lambda_metric(metric_name='nhulston.test', value=1)
    lambda_metric(metric_name='nhulston.test', value=2.5)
    lambda_metric(metric_name='nhulston.test', value="3")
    lambda_metric(metric_name='nhulston.test', value="abc")
    lambda_metric(metric_name=5, value=5)

    print('Metric sent!')

    return 200

and I see the correct 3 metrics delivered, while seeing logs

Sending metric...
[WARNING]	2025-01-21T20:38:47.187Z	aad67902-8de0-4282-9ed2-fd1b9ca5cc0d	Ignoring metric submission for metric 'nhulston.test' because the value is not numeric: '3'
[WARNING]	2025-01-21T20:38:47.187Z	aad67902-8de0-4282-9ed2-fd1b9ca5cc0d	Ignoring metric submission for metric 'nhulston.test' because the value is not numeric: 'abc'
[WARNING]	2025-01-21T20:38:47.188Z	aad67902-8de0-4282-9ed2-fd1b9ca5cc0d	Ignoring metric submission. Invalid metric name: 5
Metric sent!

Additional Notes

Types of Changes

• Bug fix
• New feature
• Breaking change
• Misc (docs, refactoring, dependency upgrade, etc.)

Check all that apply

• This PR's description is comprehensive
• This PR contains breaking changes that are documented in the description
• This PR introduces new APIs or parameters that are documented and unlikely to change in the foreseeable future
• This PR impacts documentation, and it has been updated (or a ticket has been logged)
• This PR's changes are covered by the automated tests
• This PR collects user input/sensitive content into Datadog
• This PR passes the integration tests (ask a Datadog member to run the tests)

[purple4reina]

Is there a chance that lambda_metric("kittens", "1") works? If so, then maybe we do something like

try:
  int(value)
except:
  # log warning and return
  return