Fix background color so it switches with light/dark theme.

Signed-off-by: Camila <hello@camila.codes>

src/gui/tray/TalkReplyTextField.qml

@@ -49,6 +49,7 @@ Item {
             radius: 24
             border.width: 1
             border.color: Style.ncBlue
+            color: Style.backgroundColor
         }
 
         Button {