Tells the external provider to stop delivering to the webhook URL Fruxon registered for this config — the un-install counterpart to `:applyWebhookToProvider`.

Lets an operator wind a channel down without leaving Fruxon to clear the webhook in BotFather / the provider hub. Providers with a programmatic deregistration API (Telegram `deleteWebhook` today) get a single-click disconnect; providers without one return 400 and the FE hides the affordance, exactly like the installer/inspector. No request body — removal needs no URL; it clears whatever the provider currently has registered for this config's credentials. This only stops the provider from sending; it does not delete Fruxon's webhook key (rotate/regenerate for that) or any trigger wiring. Returns 200 with `removed=false` + `errorMessage` when the provider rejects (auth failure, rate limit, network error) — the FE surfaces the message inline.

curl -X POST "https://api.fruxon.com/v1/tenants/string/integrations/string/configs/497f6eca-6276-4993-bfeb-53cbbbba6f08:removeWebhookFromProvider"

{
  "removed": false,
  "providerResponse": "string",
  "errorMessage": "string"
}

{
  "type": "string",
  "title": "string",
  "status": 0,
  "detail": "string",
  "instance": "string",
  "property1": null,
  "property2": null
}

{
  "type": "string",
  "title": "string",
  "status": 0,
  "detail": "string",
  "instance": "string",
  "property1": null,
  "property2": null
}