patchUrlMappings does not support targets with parameter matched ports

[joeynenni]

Now that the discord proxy supports targets with a custom port in the URL Mappings (confirmed it works), I have decided to file this issue again.

The current implementation of patchUrlMappings produces the following result when a client app served from 1234.discordsays.com tries making a request to 86d96a.edge.hathora.dev:51738 with a parameter matched port in the target:

patchUrlMappings([{ prefix: '/hathora/edge/{subdomain}/{port}', target: '{subdomain}.edge.hathora.dev:{port}' }])

Expected result: Client app makes a request to 1234.discordsays.com/hathora/edge/86d96a/51738 instead of 86d96a.edge.hathora.dev:51738

Actual result: An error occurs on client app on load (Uncaught TypeError: Failed to construct 'URL': Invalid URL at matchAndRewriteURL)

This error occurs because the line at https://github.com/discord/embedded-app-sdk/blob/main/src/utils/url.ts#L36 attempts to construct a new URL with the target value. However, if the target value has a non-numeric port (like the parameter matched :{port} from the example) then the URL constructor will fail.

[joeynenni]

I submitted a PR to fix this issue: #303