5bafd92edf
The slack sub-tests in TestDiscordOnly_CreateRejectsNonDiscord and TestBlocker3_CreateProviderRejectsNonDiscordWithSecurityEvents were omitting the required token field from their request payloads. CreateProvider enforces that Slack providers must have a non-empty token (the webhook URL) at creation time. Without it the service returns "slack webhook URL is required", which the handler does not classify as a 400 validation error, so it falls through to 500. Add a token field to each test struct, populate it for the slack case with a valid-format Slack webhook URL, and use WithSlackURLValidator to bypass the real format check in unit tests — matching the pattern used in all existing service-level Slack tests.