[MM-28211] API pass-thru to the CWS for getting subscription (#15666)

* API pass-thru to the CWS for getting subscription

* Remove use of parameter in favour of env var

* Remove unnecessary param

* Removed unnecessary fields and added client4 method

* Some cleanup

* Translation fix

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

model/client4.go

@@ -5650,3 +5650,16 @@ func (c *Client4) ConfirmCustomerPayment(confirmRequest *ConfirmPaymentMethodReq
 
 	return BuildResponse(r)
 }
+
+func (c *Client4) GetSubscription() (*Subscription, *Response) {
+	r, appErr := c.DoApiGet(c.GetCloudRoute()+"/subscription", "")
+	if appErr != nil {
+		return nil, BuildErrorResponse(r, appErr)
+	}
+	defer closeBody(r)
+
+	var subscription *Subscription
+	json.NewDecoder(r.Body).Decode(&subscription)
+
+	return subscription, BuildResponse(r)
+}