Fix hang in exiting konsole with Ctrl+D with QInputMethodQuery

Add missing incrementation in for loop in decodeLine()

Thanks to Takahiro Hashimoto kenya888 gmail com for research, bug and
fix.

BUG: 345294
REIVEW: 123143
(cherry picked from commit 7017a999d6)

src/TerminalCharacterDecoder.cpp

@@ -116,6 +116,8 @@ void PlainTextDecoder::decodeLine(const Character* const characters, int count,
                 const QString s = QString::fromUtf16(chars, extendedCharLength);
                 plainText.append(s);
                 i += qMax(1, string_width(s));
+            } else {
+                ++i;
             }
         } else {
             // All characters which appear before the last real character are