[MM-51236] - Add opt-in checkbox in self-hosted account creation page (#22709)

* [MM-51236] - Add opt-in checkbox in self-hosted account creation page

* add server impl

* fix lint and translations

* add tests

* improvents

* fix model

* fix mocks

* feedback impl

* update text color

* handle error

* fix tests

model/hosted_customer.go

@@ -8,6 +8,12 @@ type BootstrapSelfHostedSignupRequest struct {
 	Reset bool   `json:"reset"`
 }
 
+type SubscribeNewsletterRequest struct {
+	Email             string `json:"email"`
+	ServerID          string `json:"server_id"`
+	SubscribedContent string `json:"subscribed_content"`
+}
+
 type BootstrapSelfHostedSignupResponse struct {
 	Progress string `json:"progress"`
 	// email listed on the JWT claim