docs: add a note about installing preview version (#8648)

- Add a note about ensuring a package's version is set to `preview` in `package.json`
- Add a troubleshooting guide for deployments with a section about preview versions
- Added a troubleshooting section to the railway deployment guide about preview versions

Closes #8646
Closes DOCS-913

www/apps/resources/generated/edit-dates.mjs

@@ -131,7 +131,7 @@ export const generatedEditDates = {
   "app/contribution-guidelines/docs/page.mdx": "2024-05-13T18:55:11+03:00",
   "app/create-medusa-app/page.mdx": "2024-08-05T11:10:55+03:00",
   "app/deployment/admin/vercel/page.mdx": "2024-07-31T17:01:33+03:00",
-  "app/deployment/medusa-application/railway/page.mdx": "2024-07-31T17:01:33+03:00",
+  "app/deployment/medusa-application/railway/page.mdx": "2024-08-19T07:19:54.945Z",
   "app/deployment/storefront/vercel/page.mdx": "2024-07-26T07:21:31+00:00",
   "app/deployment/page.mdx": "2024-07-25T09:55:22+03:00",
   "app/integrations/page.mdx": "2024-07-19T08:49:08+00:00",
@@ -255,6 +255,7 @@ export const generatedEditDates = {
   "app/admin-widget-injection-zones/page.mdx": "2024-05-29T13:50:19+03:00",
   "app/architectural-modules/notification/page.mdx": "2024-07-04T17:26:03+03:00",
   "app/architectural-modules/event/create/page.mdx": "2024-07-04T17:26:03+03:00",
+  "app/troubleshooting/deployment/page.mdx": "2024-08-19T07:19:40.924Z",
   "references/core_flows/Order/functions/core_flows.Order.orderEditUpdateItemQuantityValidationStep/page.mdx": "2024-08-20T00:10:58.913Z",
   "references/core_flows/Order/functions/core_flows.Order.orderEditUpdateItemQuantityWorkflow/page.mdx": "2024-08-20T00:10:58.949Z",
   "references/core_flows/Order/functions/core_flows.Order.updateOrderEditItemQuantityValidationStep/page.mdx": "2024-08-20T00:10:59.121Z",