contrib/ffmpeg: add FEC enable to patch list

Add the patches that enable FEC in libopus codec in ffmpeg package.json
This ensures that the patches are properly applied, especially in the
Windows builds.

Issue: #5157
Change-Id: I438de63528894d3c7ded553f1982d664bda26e31

contrib/src/ffmpeg/package.json

@@ -11,7 +11,9 @@
     ],
     "patches": [
         "change-RTCP-ratio.patch",
-        "rtp_ext_abs_send_time.patch"
+        "rtp_ext_abs_send_time.patch",
+        "libopusenc-enable-FEC.patch",
+        "libopusdec-enable-FEC.patch"
     ],
     "win_patches": [
         "windows-configure.patch",