feat: 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

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

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[ldhenry]

Looks good so far 👍🏼

[ember-stevens]

✅ from Docs for the copy

[sasthana-ld]

Ah closing this as created this PR from wrong branch name (didn't follow the JIRA steps to generate the branch and PR) closing this against #348