Use single-node USER_ISOLATION cluster by default when managing `databricks_sql_permissions` resources

[mgyucht]

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Changes

In https://github.com/databricks/terraform-provider-databricks/commit/27ad78de516e5baf98c64ae92e7815faecc9e153, we modified the default cluster launched by the databricks_sql_permissions resource to use a cluster with a worker node. This was done to mitigate an issue where it was no longer possible to create single-node clusters with legacy Table ACLs. Since the start of May, single-node USER_ISOLATION clusters are supported and can be used to manage Table ACLs. This PR changes this resource to use such a cluster going forward.

Tests

Covered by existing integration tests.

[github-actions[bot]]

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Inputs:

• PR number: 4778
• Commit SHA: b54bf010a68eecd82c84decef78617b1cf7836b8

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[alexott]

Closing in favor of #4813