feat: [MTRX-1308] Add archived field to launchdarkly_metrics resources

[sasthana-ld]

Adds archived boolean field to launchdarkly_metric resource to allow users to mark metrics as archived through Terraform.

added TO-DO comments for api client since ldapi.MetricPost does not support Archived field yet so when LD api client is merged I will uncomment the archived field code in create/update operations

made changes as we have discussed in Tech spec: https://docs.google.com/document/d/1HKRRgdSnHoXjrLnzRY9_7hQw4Q5pW9Q_AQdpO0wTm9w/edit?tab=t.0#heading=h.lcgpt7k0oisq

Jira Ticket: https://launchdarkly.atlassian.net/browse/MTRX-1308

DB PR: https://github.com/launchdarkly/gonfalon/pull/51985
Backend PR: https://github.com/launchdarkly/gonfalon/pull/51995

Wait!

• Have you added comprehensive tests?
• Have you updated relevant data sources as well as resources?
• Have you updated the docs?

Testing

For any changes you make, please ensure your acceptance test conform to the following:

• every single new attribute is tested
• optional attributes revert to null or default values if removed
• attributes that interact interact as expected
• block values behave as expected when reordered
• nested fields on maps or list/set items function as expected. Terraform does not actually enforce most schema attributes on nested items
• each test step for a configuration is followed by a test step where ImportState and ImportStateVerify are set to true. ImportStateVerifyIgnore can be used if we explicitly expect a value to be different when imported, such as in the case of obfuscated values like API keys

LaunchDarkly Employees

For more information on how to build, test, and release, see the internal provider runbook.

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Related Jira issue: MTRX-1308: Add archived field support to launchdarkly_metric Terraform resource

[ldhenry]

Looking good so far. Feel free to request a review of myself or @sloloris when you are ready.

[ember-stevens]

✅ for the docs updates