GUI: Do not abuse the engine name query item to provide a summary

The redirect rule on the web site expected only two query items, one
with the engine name and another one with the description. However it
was a bit lax in its regex and we could pass additional query items
as part of either the engine name or description. The unknown game
dialog was abusing it to pass a summary.

The rewrite rule for the URL on the web site has now been fixed to
avoid such abuse. And instead it also adds a summary. So the
unknown name dialog should no longer provide one.

gui/unknown-game-dialog.cpp

@@ -202,10 +202,8 @@ Common::String UnknownGameDialog::generateBugtrackerURL() {
 	return Common::String::format(
 		"https://www.scummvm.org/unknowngame?"
 		"engine=%s"
-		"&summary=Unknown game variant for %s"
 		"&description=%s",
 		engineName.c_str(),
-		engineName.c_str(),
 		report.c_str());
 }