Spring-ai Fix Anthropic chat model functioncalling token usage

• Accumulate the token usage when functioncalling is used

• Fix both call() as well as stream() operations

• Add/update tests

Comment From: tzolov

LGTM, thanks @ilayaperumalg

Comment From: tzolov

rebased and merged at cadea8b7302c5cbc61525712006ad3b78ac84d8d