Fix color modulation of the grayscale glyphs in font with mixed color / grayscale data.

(cherry picked from commit 4d0c0f3ffac92a7239d321001650367730ef8667)

scene/resources/dynamic_font.cpp

@@ -523,7 +523,7 @@ float DynamicFontAtSize::draw_char(RID p_canvas_item, const Point2 &p_pos, CharT
 			cpos.y -= font->get_ascent();
 			cpos.y += ch->v_align;
 			Color modulate = p_modulate;
-			if (FT_HAS_COLOR(font->face)) {
+			if (font->textures[ch->texture_idx].texture->get_format() == Image::FORMAT_RGBA8) {
 				modulate.r = modulate.g = modulate.b = 1.0;
 			}
 			RID texture = font->textures[ch->texture_idx].texture->get_rid();