What is meant by the term "galvanic contact" in this sentence?
You're right about galvanic cells, but the word has picked up other usages. As usual with human language, there's no guarantee of logical consistency in these developments.

Galvanic contact and galvanic isolation simply refer to the presence or absence of a direct electrical connection. That is, a current through a conductor, rather than a connection via capacitive or inductive coupling, optical coupling, and so on.

In my experience, galvanic isolation is much the more common term. For example, transformers and optocouplers provide galvanic isolation. Galvanic contact makes sense as a consistent antonym, but I haven't seen it used anywhere near as much.