feat: add support for datadog metrics in third_party_integration

[francovp]

Description

Adds support for sendCollectionLatencyMetrics and sendDatabaseMetrics in the Datadog third_party_integration resource and data sources as they are supported by the atlas API

Updates documentation and example configurations to reflect these new options.

Link to any related issue(s):

https://feedback.mongodb.com/forums/924145-atlas/suggestions/49619627-add-sendcollectionlatencymetrics-and-senddatabasem

Type of change:

• Bug fix (non-breaking change which fixes an issue). Please, add the "bug" label to the PR.
• New feature (non-breaking change which adds functionality). Please, add the "enhancement" label to the PR. A migration guide must be created or updated if the new feature will go in a major version.
• Breaking change (fix or feature that would cause existing functionality to not work as expected). Please, add the "breaking change" label to the PR. A migration guide must be created or updated.
• This change requires a documentation update
• Documentation fix/enhancement

Required Checklist:

• I have signed the MongoDB CLA
• I have read the contributing guides
• I have checked that this change does not generate any credentials and that they are NOT accidentally logged anywhere.
• I have added tests that prove my fix is effective or that my feature works per HashiCorp requirements
• I have added any necessary documentation (if appropriate)
• I have run make fmt and formatted my code
• If changes include deprecations or removals I have added appropriate changelog entries.
• If changes include removal or addition of 3rd party GitHub actions, I updated our internal document. Reach out to the APIx Integration slack channel to get access to the internal document.

Further comments

[maastha]

Thanks a lot @francovp for creating this PR!

As per our guidelines, I will work on running our tests & incorporating this change into our provider.

[github-actions]

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[francovp]

Closing as this was implemented in #3259