feat: Update Rokt methods to match v5

[jamesnrokt]

Background

• Pending the release of Rokt 5.0 this PR updates our integration to use the new methods
• Copy of the PR feat: Update Rokt methods to match v5 mparticle-integrations/mparticle-apple-integration-rokt#44

What Has Changed

• Updated to use the new Rokt selectPlacementsWithIdentifier and init methods

Screenshots/Video

• N/A

Checklist

• I have performed a self-review of my own code.
• I have made corresponding changes to the documentation.
• I have added tests that prove my fix is effective or that my feature works.
• I have tested this locally.

Additional Notes

• Untested and in draft pending the final release of Rokt 5.0

Reference Issue (For employees only. Ignore if you are an outside contributor)

• Closes https://go/j/[ticket-number]

[github-actions]

📦 SDK Size Impact Report

Measures how much the SDK adds to an app's size (with-SDK minus without-SDK).

Metric	Target Branch	This PR	Change
App Bundle Impact	1.65 MB	1.65 MB	+N/A
Executable Impact	896 bytes	896 bytes	+N/A
XCFramework Size	5.45 MB	5.45 MB	+N/A

➡️ SDK size impact change is minimal.

Raw measurements

Target branch (workstation/9.0-Release):

{"baseline_app_size_kb":84,"baseline_executable_size_bytes":75464,"with_sdk_app_size_kb":1772,"with_sdk_executable_size_bytes":76360,"sdk_impact_kb":1688,"sdk_executable_impact_bytes":896,"xcframework_size_kb":5584}

This PR:

{"baseline_app_size_kb":84,"baseline_executable_size_bytes":75464,"with_sdk_app_size_kb":1772,"with_sdk_executable_size_bytes":76360,"sdk_impact_kb":1688,"sdk_executable_impact_bytes":896,"xcframework_size_kb":5584}