website: Add Framework Migration Guide Links

[Brian Flad]

SDK version

v2.24.0

Use-cases

The terraform-plugin-framework documentation now includes a migration guide section. Currently the SDK overview page and SDK side navigation omit linking over to this guide.

Proposal

• Update website/docs/plugin/sdkv2/index.mdx to include a link to /plugin/framework/migrating.
• Update website/data/plugin-sdk-nav-data.json to include a href link (not path) to https://developer.hashicorp.com/terraform/plugin/framework/migrating

[github-actions]

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