fix(apple): Fix undefined variable in config block

[rromanchuk]

DESCRIBE YOUR PR

Example does not compile. Align yielded block variable name in scope and match objective-c name

IS YOUR CHANGE URGENT?

None: Not urgent, can wait up to 1 week+

SLA

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• Please give the docs team up to 1 week to review your PR unless you've added an urgent due date to it. Thanks in advance for your help!

PRE-MERGE CHECKLIST

Make sure you've checked the following before merging your changes:

• [ ] Checked Vercel preview for correctness, including links
• [ ] PR was reviewed and approved by any necessary SMEs (subject matter experts)
• [ ] PR was reviewed and approved by a member of the Sentry docs team

LEGAL BOILERPLATE

Look, I get it. The entity doing business as "Sentry" was incorporated in the State of Delaware in 2015 as Functional Software, Inc. and is gonna need some rights from me in order to utilize my contributions in this here PR. So here's the deal: I retain all rights, title and interest in and to my contributions, and by keeping this boilerplate intact I confirm that Sentry can use, modify, copy, and redistribute my contributions, under Sentry's choice of terms.

[vercel[bot]]

@rromanchuk is attempting to deploy a commit to the Sentry Team on Vercel.

A member of the Team first needs to authorize it.

[philipphofmann]

Bypassing merging rules, because PR is OK, but has authorization issues for deploying to Vercel because of a contributor.