decoder/opus: move comment size check to ScanOneOpusTag()

src/decoder/plugins/OpusTags.cxx

@@ -45,6 +45,10 @@ ScanOneOpusTag(StringView name, StringView value,
 	       ReplayGainInfo *rgi,
 	       TagHandler &handler) noexcept
 {
+	if (value.size >= 4096)
+		/* ignore large values */
+		return;
+
 	if (rgi != nullptr && name.EqualsIgnoreCase("R128_TRACK_GAIN")) {
 		/* R128_TRACK_GAIN is a Q7.8 fixed point number in
 		   dB */
@@ -97,9 +101,6 @@ ScanOpusTags(const void *data, size_t size,
 		if (s == nullptr)
 			return false;
 
-		if (s.size >= 4096)
-			continue;
-
 		const auto split = s.Split('=');
 		if (split.first.empty() || split.second.IsNull())
 			continue;