Ensure that mode updates are always sent when ddos_protection is enabled

[philippschulte]

Change summary

Fixes #1148.

Previously, changes to ddos_protection.mode (e.g. from "block" to "log") were not sent to the Fastly API if the target mode was "log", due to a conditional check that skipped the update. This caused persistent diffs and unexpected behavior.

This pull request removes the conditional check and ensures that mode updates are always sent when ddos_protection is enabled.

All Submissions:

• Have you followed the guidelines in our Contributing document?
• Have you checked to ensure there aren't other open Pull Requests for the same update/change?

Changes to Core Features:

• Have you written new tests for your core changes, as applicable?
• Have you successfully run tests with your changes locally?

=== RUN   TestAccFastlyServiceVCLProductEnablement_basic
=== PAUSE TestAccFastlyServiceVCLProductEnablement_basic
=== CONT  TestAccFastlyServiceVCLProductEnablement_basic
--- PASS: TestAccFastlyServiceVCLProductEnablement_basic (14.98s)

=== RUN   TestAccFastlyServiceVCLProductEnablement_ddosProtectionModeChange
=== PAUSE TestAccFastlyServiceVCLProductEnablement_ddosProtectionModeChange
=== CONT  TestAccFastlyServiceVCLProductEnablement_ddosProtectionModeChange
--- PASS: TestAccFastlyServiceVCLProductEnablement_ddosProtectionModeChange (41.45s)

[kpfleming]

Indeed, thanks for the fix. I wonder if we have any other 'optimizations' in place which do similar things.