[fix] Set default creation options when importing retool_space resource

[ph-ph]

Description

While experimenting with auto-generated TF code, I noticed that TF always wants to delete and create a space again, even when we're importing an existing space:

  # retool_space.dev_terraform_retool_dev must be replaced
  # (imported from "org_546e2e6bfe2945d38a063b0bd1b112c1")
  # Warning: this will destroy the imported resource
-/+ resource "retool_space" "dev_terraform_retool_dev" {
      + create_options = { # forces replacement
          + copy_branding_and_themes_settings = false
          + copy_sso_settings                 = false
          + create_admin_user                 = true
          + users_to_copy_as_admins           = []
        }
        domain         = "dev.terraform.retool.dev"
      ~ id             = "org_546e2e6bfe2945d38a063b0bd1b112c1" -> (known after apply)
        name           = "Dev Space"
    }

That's because create_options attribute is configured as requires replace - any change in the options would require TF to delete existing space and create a new one, to make sure it's created with the right options.

What happens during the import is:

• TF creates new resource for the space, and sets create_options to null.
• It then "remembers" that create_options has default value and sets it.
• Now it looks like create_options has changed, so the space must be destroyed and created again.

Long story short, this change simply sets create_options to default value on import .

Tests

• Tested the import scenario with my local build of the provider, verified that it doesn't attempt to re-create the space now:

  # retool_space.dev_terraform_retool_dev will be imported
    resource "retool_space" "dev_terraform_retool_dev" {
        create_options = {
            copy_branding_and_themes_settings = false
            copy_sso_settings                 = false
            create_admin_user                 = true
            users_to_copy_as_admins           = []
        }
        domain         = "dev.terraform.retool.dev"
        id             = "org_546e2e6bfe2945d38a063b0bd1b112c1"
        name           = "Dev Space"
    }

• Updated the acceptance test to verify new behavior.