Change SchemaFactory.identifier to a function in v3.0

[jason-ha]

Broken API or pattern

Accessing SchemaFactory.identifier as a property returns a function, which when called returns a read-only field holding an identifier for the node.

Preparation References

When updating to v3.0 or later, replace any SchemaFactory.identifier accesses with SchemaFactory.identifier().

Packages

@fluidframework/tree

Expected Timeline

v3.0