Change response code of special settings API endpoints to 204

refs https://github.com/TryGhost/Toolbox/issues/308

- these endpoints return no body but they were implemented to return a
  200 error code
- 204 would be more suitable so this commit changes that for v5
- also removes the passthrough serializer and updates the snapshots to
  reflect the changes

core/server/api/canary/settings.js

@@ -96,6 +96,7 @@ module.exports = {
     },
 
     updateMembersEmail: {
+        statusCode: 204,
         permissions: {
             method: 'edit'
         },
@@ -122,6 +123,7 @@ module.exports = {
     },
 
     disconnectStripeConnectIntegration: {
+        statusCode: 204,
         permissions: {
             method: 'edit'
         },

core/server/api/canary/utils/serializers/output/settings.js

@@ -86,7 +86,5 @@ module.exports = {
     download: serializeData,
     upload: serializeData,
 
-    updateMembersEmail: passthrough,
     validateMembersEmailUpdate: passthrough,
-    disconnectStripeConnectIntegration: passthrough
 };

test/e2e-api/admin/__snapshots__/settings.test.js.snap

@@ -1127,10 +1127,8 @@ exports[`Settings API can do disconnectStripeConnectIntegration 1: [headers] 1`]
 Object {
   "access-control-allow-origin": "http://127.0.0.1:2369",
   "cache-control": "no-cache, private, no-store, must-revalidate, max-stale=0, post-check=0, pre-check=0",
-  "content-length": "2",
-  "content-type": "application/json; charset=utf-8",
   "etag": StringMatching /\\(\\?:W\\\\/\\)\\?"\\(\\?:\\[ !#-\\\\x7E\\\\x80-\\\\xFF\\]\\*\\|\\\\r\\\\n\\[\\\\t \\]\\|\\\\\\\\\\.\\)\\*"/,
-  "vary": "Origin, Accept-Encoding",
+  "vary": "Origin",
   "x-powered-by": "Express",
 }
 `;
@@ -1139,10 +1137,8 @@ exports[`Settings API can do updateMembersEmail 1: [headers] 1`] = `
 Object {
   "access-control-allow-origin": "http://127.0.0.1:2369",
   "cache-control": "no-cache, private, no-store, must-revalidate, max-stale=0, post-check=0, pre-check=0",
-  "content-length": "2",
-  "content-type": "application/json; charset=utf-8",
   "etag": StringMatching /\\(\\?:W\\\\/\\)\\?"\\(\\?:\\[ !#-\\\\x7E\\\\x80-\\\\xFF\\]\\*\\|\\\\r\\\\n\\[\\\\t \\]\\|\\\\\\\\\\.\\)\\*"/,
-  "vary": "Origin, Accept-Encoding",
+  "vary": "Origin",
   "x-powered-by": "Express",
 }
 `;

test/e2e-api/admin/settings.test.js

@@ -171,7 +171,7 @@ describe('Settings API', function () {
                 email: 'test@test.com',
                 type: 'fromAddressUpdate'
             })
-            .expectStatus(200)
+            .expectStatus(204)
             .expectEmptyBody()
             .matchHeaderSnapshot({
                 etag: anyEtag
@@ -206,7 +206,7 @@ describe('Settings API', function () {
     it('can do disconnectStripeConnectIntegration', async function () {
         await agent
             .delete('/settings/stripe/connect/')
-            .expectStatus(200)
+            .expectStatus(204)
             .expectEmptyBody()
             .matchHeaderSnapshot({
                 etag: anyEtag