Access GraphiQL on remote URL

[amcaplan]

WHY are these changes introduced?

Fixes #4223

We aren't able to access GraphiQL on a remote environment because the localhost URL is hardcoded.

WHAT is this pull request doing?

Pulls the URL from the request context, so even if it's behind a tunnel or proxy, the URLs will be correctly formed from the perspective of the browser.

How to test your changes?

1. Run an HTTPS tunnel to localhost:3457
2. p shopify app dev --path /path/to/your/app --graphiql-key=abcdef
3. Hit g to open up GraphiQL. It will give an error page. Add ?key=abcdef to your URL and then it should work.
4. Replace localhost:3457 with your tunnel URL on https. Everything should still work properly, including firing a GraphQL query.
5. Try uninstalling your app and going through the install flow from GraphiQL. Things should work as normal.

Measuring impact

How do we know this change was effective? Please choose one:

• [x] n/a - this doesn't need measurement, e.g. a linting rule or a bug-fix
• [ ] Existing analytics will cater for this addition
• [ ] PR includes analytics changes to measure impact

Checklist

• [x] I've considered possible cross-platform impacts (Mac, Linux, Windows)
• [x] I've considered possible documentation changes

[github-actions[bot]]

We detected some changes at either packages/*/src or packages/cli-kit/assets/cli-ruby/** and there are no updates in the .changeset. If the changes are user-facing, run "pnpm changeset add" to track your changes and include them in the next release CHANGELOG.

[github-actions[bot]]

Coverage report

St.:grey_question:	Category	Percentage	Covered / Total
🟡	Statements	73.28% (+0.09% 🔼)	8209/11203
🟡	Branches	69.65% (-0.01% 🔻)	3990/5729
🟡	Functions	71.85% (+0.03% 🔼)	2149/2991
🟡	Lines	73.6% (+0.1% 🔼)	7764/10549

Show files with reduced coverage 🔻

St.:grey_question:	File	Statements	Branches	Functions	Lines
🔴	... / server.ts	1.28% (-0.02% 🔻)	0%	0%	1.35% (-0.02% 🔻)
🟢	... / ConcurrentOutput.tsx	98.39% (-1.61% 🔻)	90.91% (-4.55% 🔻)	100%	98.33% (-1.67% 🔻)

Test suite run success

1854 tests passing in 846 suites.

Report generated by 🧪jest coverage report action from ef1a724ff4c32b62d2e06a286a7c40dbaa392769

[amcaplan]

I'm electing to leave out a changeset, as we have not fully documented this feature yet - we still hide the --graphiql-key param and aren't documenting it. We need to make some time eventually to publish some sort of guide to how to use GraphiQL in app dev in the cloud.