Adjust initialization lifecycle wording to account for stateless usage

Author: Zachary German

docs/specification/draft/basic/lifecycle.mdx

@@ -39,7 +39,7 @@ sequenceDiagram
 
 ### Initialization
 
-The initialization phase **MUST** be the first interaction between client and server.
+The initialization phase **MAY** be the first interaction between client and server.
 During this phase, the client and server:
 
 - Establish protocol version compatibility