Add RTCEncodedFrameMetadata to externs

This type was added to Typescript 5.9.

PiperOrigin-RevId: 886975967

Author: Googler

java/elemental2/dom/integer_entities.txt

@@ -389,12 +389,14 @@ elemental2.dom.RTCError.getReceivedAlert
 elemental2.dom.RTCError.getSctpCauseCode
 elemental2.dom.RTCError.getSdpLineNumber
 elemental2.dom.RTCError.getSentAlert
+elemental2.dom.RTCEncodedFrameMetadata.getPayloadType
+elemental2.dom.RTCEncodedFrameMetadata.setPayloadType.payloadType
+elemental2.dom.RTCEncodedAudioFrameMetadata.getSequenceNumber
+elemental2.dom.RTCEncodedAudioFrameMetadata.setSequenceNumber.sequenceNumber
 elemental2.dom.RTCEncodedVideoFrameMetadata.getFrameId
 elemental2.dom.RTCEncodedVideoFrameMetadata.setFrameId.frameId
 elemental2.dom.RTCEncodedVideoFrameMetadata.getHeight
 elemental2.dom.RTCEncodedVideoFrameMetadata.setHeight.height
-elemental2.dom.RTCEncodedVideoFrameMetadata.getPayloadType
-elemental2.dom.RTCEncodedVideoFrameMetadata.setPayloadType.payloadType
 elemental2.dom.RTCEncodedVideoFrameMetadata.getSpatialIndex
 elemental2.dom.RTCEncodedVideoFrameMetadata.setSpatialIndex.spatialIndex
 elemental2.dom.RTCEncodedVideoFrameMetadata.getTemporalIndex