js-find-symbol/js--read-symbol reads a symbol via ido-completing-read
and automatically activates ido-mode. For users of other completion
systems (default completion, Icomplete/Fido, Vertico, Helm, ...) this is
not desired. Icomplete/Fido/Vertico/etc. replace Ido and provide similar
behavior for general completing-read.

Patch attached.