chore: restore error and deprecate it (#11800)

* chore: restore error and deprecate it

* change deprecation version

* Update packages/astro/src/core/errors/errors-data.ts

packages/astro/src/core/errors/errors-data.ts

@@ -1664,6 +1664,22 @@ export const ActionsWithoutServerOutputError = {
 	hint: 'Learn about on-demand rendering: https://docs.astro.build/en/basics/rendering-modes/#on-demand-rendered',
 } satisfies ErrorData;
 
+/**
+ * @docs
+ * @see
+ * - [Actions RFC](https://github.com/withastro/roadmap/blob/actions/proposals/0046-actions.md)
+ * @description
+ * Action was called from a form using a GET request, but only POST requests are supported. This often occurs if `method="POST"` is missing on the form.
+ * @deprecated Deprecated since version 4.13.2.
+ */
+export const ActionsUsedWithForGetError = {
+	name: 'ActionsUsedWithForGetError',
+	title: 'An invalid Action query string was passed by a form.',
+	message: (actionName: string) =>
+		`Action ${actionName} was called from a form using a GET request, but only POST requests are supported. This often occurs if \`method="POST"\` is missing on the form.`,
+	hint: 'Actions are experimental. Visit the RFC for usage instructions: https://github.com/withastro/roadmap/blob/actions/proposals/0046-actions.md',
+} satisfies ErrorData;
+
 /**
  * @docs
  * @see