Updated documentation - How to disable IDFA collection (ios)

[Siddharth1605]

Description

Updated the documentation to include the 'without idfa' dependency (ios)

Related Issues

Issue Number: #12081 Issue : Document how to disable IDFA collection (iOS)

Checklist

• [x] I read the [Contributor Guide] and followed the process outlined there for submitting PRs.
• [x] My PR includes unit or integration tests for all changed/updated/fixed behaviors (See [Contributor Guide]).
• [x] All existing and new tests are passing.
• [x] I updated/added relevant documentation (doc comments with ///).
• [x] The analyzer (melos run analyze) does not report any problems on my PR.
• [x] I read and followed the [Flutter Style Guide].
• [x] I signed the [CLA].
• [x] I am willing to follow-up on review comments in a timely manner.

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