app_server: fix fallback for fonts where the variants match.

This does not produce a satisfactory fallback if i.e "extrabold"
is selected since the CJK font does not have that, probably need to
figure out a way to change the font style so that it renders correctly
(render cjk as bold when display is at extrabold or so).

Fixes #15751.

Signed-off-by: Augustin Cavalier <waddlesplash@gmail.com>

src/servers/app/font/GlyphLayoutEngine.h

@@ -335,8 +335,9 @@ GlyphLayoutEngine::_WriteLockAndAcquireFallbackEntry(
 	// Try to get the glyph from the fallback fonts
 	while (fallbacks[i] != NULL) {
 		if (gFontManager->Lock()) {
-			FontStyle* fallbackStyle = gFontManager->GetStyleByIndex(
-				fallbacks[i], 0);
+			FontStyle* fallbackStyle = gFontManager->GetStyle(
+				fallbacks[i], font.Style());
+
 			if (fallbackStyle != NULL) {
 				ServerFont fallbackFont(*fallbackStyle, font.Size());
 				gFontManager->Unlock();