Remove Authenticate call from TF Configure

[mgyucht]

Changes

Now that the SDK always uses context.Background() for refreshing OAuth tokens, we don't need to authenticate in the provider configure method with a background context anymore. This removes the need to handle edge cases in the provider configure method around authentication failures, like that described in #3023.

Resolves #3023.

Tests

Applied the following template using OAuth-M2M authentication:

resource "databricks_notebook" "example" {
    content_base64 = base64encode(<<-EOT
        # created from ${abspath(path.module)}
        display(spark.range(3))
        EOT
    )
    language = "PYTHON"
    path = "/Shared/HelloWorld"
}
resource "time_sleep" "wait_2_hours" {
  depends_on = [databricks_notebook.previous]

  create_duration = "2h"
}
resource "databricks_notebook" "example2" {
    content_base64 = base64encode(<<-EOT
        # created from ${abspath(path.module)}
        display(spark.range(4))
        EOT
    )
    language = "PYTHON"
    path = "/Shared/HelloWorldAfterWait"
    depends_on = [ time_sleep.wait_2_hours ]
}

This should be long enough that the OAuth token expires and a new access token is retrieved to update the last notebook.

[nfx]

lgtm