chore: Combine migrating docs

[jamesnrokt]

Background

• Combines the two migrating docs into a single one

What Has Changed

• Migrating docs

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

• N/A

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

• Closes N/A

[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}