Fix duplicated slashes when deploying webhooks with relative URIs

[gonzaloriestra]

WHY are these changes introduced?

Related to #4298 (comment)

WHAT is this pull request doing?

When you deploy an app with:

• Application URL including a final slash (default value in the template), like https://example.com/
• Webhook with a relative URI, like /webhooks

Then the webhook is registered with a duplicated slash in Partners: https://example.com//webhooks

How to test your changes?

• p shopify app deploy

Measuring impact

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

• 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

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

[github-actions]

Thanks for your contribution!

Depending on what you are working on, you may want to request a review from a Shopify team:

• Themes: @shopify/advanced-edits
• UI extensions: @shopify/ui-extensions-cli
  • Checkout UI extensions: @shopify/checkout-ui-extensions-api-stewardship
• Hydrogen: @shopify/hydrogen
• Other: @shopify/app-inner-loop

[gonzaloriestra]

/snapit

[github-actions]

🫰✨ Thanks @gonzaloriestra! Your snapshot has been published to npm.

Test the snapshot by intalling your package globally:

pnpm i -g @shopify/cli@0.0.0-snapshot-20240821094628

After installing, validate the version by running just shopify in your terminal
If the versions don't match, you might have multiple global instances installed.
Use which shopify to find out which one you are running and uninstall it.

[github-actions]

Coverage report

St.❔	Category	Percentage	Covered / Total
🟡	Statements	73.28% (+0.12% 🔼)	8210/11203
🟡	Branches	69.66% (+0.07% 🔼)	3991/5729
🟡	Functions	71.85% (+0.03% 🔼)	2149/2991
🟡	Lines	73.61% (+0.12% 🔼)	7765/10549

Test suite run success

1854 tests passing in 846 suites.

Report generated by 🧪jest coverage report action from 97aade1