getTokenValue evaluating ID throws 100s of log warnings

Problem/Motivation

View fields plugin throws warning errors filling up logs on all view displays.
While I don't know the scenario for why the ID is empty.
But it's not catched ahead of the function causing a warning in PHP 8.1

Steps to reproduce

View any view display with fields.

Proposed resolution

Add ID detection and if missing provide empty string.

Patch attached.