vocab : keep </s> NORMAL in PLaMo-2 and PLaMo-3 (#29580)
* vocab : keep </s> NORMAL in PLaMo-2 and PLaMo-3
The PLaMo-2 and PLaMo-3 vocabularies mark </s> as NORMAL. Current
EOG token heuristic matched it by text and added its attribute
to CONTROL.
Skip this heuristic for the PLAMO2 vocab type so </s> stays NORMAL
and is not treated as EOG.
* use <|plamo:eos|> for detection
