next.js

55cdf2b2 - ensure cookies set in middleware can be read in a server action (#67924)

ensure cookies set in middleware can be read in a server action (#67924) If middleware targets a server action handler and sets or updates a cookie, the newly updated cookie would not be reflected in the `cookies()` response of the action handler In #65008 we fixed a bug where cookies set in middleware were not reflected in the `cookies()` call in a server component from the same request. We did this by introducing a `x-middleware-set-cookie` header, that signaled to downstream handlers that middleware had run on the request & set a cookie. However this handling was only applied to the sealed/read-only cookies. Cookies accessed from a server action use `mutableCookies`, since those aren't frozen as a server action is allowed to modify cookies. This pulls the cookie merge handling into a function and applies the merge to `mutableCookies`. Fixes #67814 Closes NDX-95