[FIX] [RUM-13466] iOS: fix AnyEncodable attribute decoding

[marco-saia-datadog]

What does this PR do?

On iOS, it replaces usages of the existing AnyEncodable internal definition with the imported AnyEncodable from DatadogInternal.

Motivation

When the IOS SDK decodes attributes before attaching them to the events, it expects dictionary-like objects to be of AnyEncodable (DatadogInternal), while currently they are of type DdSdkReactNative.AnyEncodable. This results in the final object to be nil.

In this specific case, it is blocking us from propagating the request and response headers from the JS layer down to the native event.

TODO: Regression Testing

• Call setUser with an extraInfo containing nested objects and verify the data arrives correctly on the native event
• Call setAccount with an extraInfo containing nested objects and verify the data arrives correctly on the native event
• Call addAttribute / addAttributes with a nested object value and verify it appears correctly on RUM events
• Call addAttribute / addAttributes with an array value and verify it appears correctly on RUM events
• Set a global attribute with a nested object and verify it persists correctly across views
• Send a log with a nested object attribute and verify the attribute arrives correctly
• Start a trace span with a nested object tag and verify it arrives correctly
• Verify nested structures are preserved (e.g., { a: { b: 1 } } is not flattened)
• Verify arrays of objects remain intact
• Verify primitive values inside nested objects keep their types (e.g., integers remain integers, not stringified)

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Review checklist (to be filled by reviewers)

• Feature or bugfix MUST have appropriate tests
• Make sure you discussed the feature or bugfix with the maintaining team in an Issue
• Make sure each commit and the PR mention the Issue number (cf the CONTRIBUTING doc)
• If this PR is auto-generated, please make sure also to manually update the code related to the change

[Copilot]

Pull request overview

This PR fixes iOS attribute decoding by removing the module-local AnyEncodable implementation and standardizing on DatadogInternal.AnyEncodable, matching what the iOS SDK expects when decoding nested/dictionary-like attributes.

Changes:

• Import DatadogInternal in the attribute-casting utilities and rely on its AnyEncodable instead of a local wrapper.
• Update unit tests to cast nested attributes using AnyEncodable (from DatadogInternal).
• Add DatadogInternal import in AnyEncodableTests.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
packages/core/ios/Sources/AnyEncodable.swift	Switches to DatadogInternal.AnyEncodable and removes the local AnyEncodable type implementation.
packages/core/ios/Tests/DdSdkTests.swift	Updates nested extraInfo assertions to cast using AnyEncodable (expected SDK type).
packages/core/ios/Tests/AnyEncodableTests.swift	Imports DatadogInternal so tests compile against the SDK’s AnyEncodable.

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