fix: duplicate ld+json data

[michael-genson]

What type of PR is this?

(REQUIRED)

• bug

What this PR does / why we need it:

(REQUIRED)

Fixes the duplicate ld+json data causing scrapers to grab the wrong recipes. I used two different solutions:

1. the data is injected only in the instance of the HTML being served, rather than the global state
2. the injected data replaces the existing data, if it exists, rather than just appending it (this ensures if there are any other instances of the metadata being injected, there is exactly one instance of recipe metadata)

Due to how our metadata injection works, technically the recipe's data follows you around (for example, if you open a recipe for chocolate brownies, then head to the home page, the chocolate brownie metadata is still present) however I tested this and it's always correct when navigating to any page directly (which is all that matters for scrapers).

Which issue(s) this PR fixes:

(REQUIRED)

Fixes #3068
Fixes #3374

Testing

(fill-in or delete this section)

Built a production instance locally and verified that exactly one instance of recipe metadata is present, and it's the correct recipe.

[michael-genson]

@hay-kot if you could confirm this works on a local prod instance that would be great. I did prior to the latest commit so I'm pretty confident it works, but it would be good to verify.

I wanted to myself but local prod isn't working (probably WSL)

[michael-genson]

Fixed my local prod and confirmed it still works as expected

[boc-the-git]

LGTM 🚀