`findApplicationById` redacts `githubPrivateKey` from the `github`
relation, but `createPreviewDeployment` passed that redacted object
straight to `authGithub`. Since `haveGithubRequirements` requires the
private key, it always returned false and `authGithub` threw
`TRPCError NOT_FOUND: "Github Account not configured correctly"`.
That throw is uncaught in `pages/api/deploy/github.ts`, so every
`pull_request` webhook returned a bare 500 and no preview deployment
was ever created.
Resolve the provider through `findGithubById(application.githubId)`
instead, matching how every other call site obtains credentials. This
keeps the redaction introduced for `findApplicationById` intact.
Fixes#4898
Co-Authored-By: Claude Opus 5 <[email protected]>