Update default TopP to 0.4

TopP 0.1 was found to be somewhat too aggressive, so a more moderate default of 0.4 would be better suited for general use.

Signed-off-by: AMOGUS <137312610+Amogus8P@users.noreply.github.com>

gpt4all-chat/modellist.h

@@ -108,7 +108,7 @@ private:
     QString m_name;
     QString m_filename;
     double  m_temperature         = 0.7;
-    double  m_topP                = 0.1;
+    double  m_topP                = 0.4;
     int     m_topK                = 40;
     int     m_maxLength           = 4096;
     int     m_promptBatchSize     = 128;