Surface `local_capture_clock_offset` from `RtpSource`

- Propagating `RtpPacketInfo::local_capture_clock_offset`, an
  existing field that is related to the abs-capture-timestamp
  header extension field `estimated_capture_clock_offset`
- Propagated through `SourceTracker::SourceEntry`

Bug: webrtc:10739, b/246753278
Change-Id: I21d9841e4f3a35da5f8d7b31582898309421d524
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/275241
Reviewed-by: Tomas Gunnarsson <tommi@webrtc.org>
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Commit-Queue: Alessio Bazzica <alessiob@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#38129}
diff --git a/api/rtp_packet_info_unittest.cc b/api/rtp_packet_info_unittest.cc
index 80abccc..d35edf7 100644
--- a/api/rtp_packet_info_unittest.cc
+++ b/api/rtp_packet_info_unittest.cc
@@ -9,6 +9,7 @@
  */
 
 #include "api/rtp_packet_infos.h"
+#include "api/units/time_delta.h"
 #include "test/gmock.h"
 #include "test/gtest.h"
 
@@ -186,7 +187,7 @@
 }
 
 TEST(RtpPacketInfoTest, LocalCaptureClockOffset) {
-  constexpr absl::optional<int64_t> kValue = 10;
+  constexpr TimeDelta kValue = TimeDelta::Micros(8868963877546349045LL);
 
   RtpPacketInfo lhs;
   RtpPacketInfo rhs;