Work Item

The deprecated readonly property should be removed from the following interfaces/classes after two version releases (0.55).

1. IDeltaManager
2. DeltaManager
3. DeltaManagerProxy
4. MockDeltaManager

Approach
Remove the property and replace any uses of the property with readOnlyInfo.readonly.

Steps

• Replace all usages of readonly with readOnlyInfo.readonly in partner repos
• Remove from FluidFramework repo

Additional context
Issue: #8190
PR: #8385