Specify the video ID used in the Widevine DASH samples in the demo app

This value is the default used by widevine_test at
proxy.uat.widevine.com, but it's not easy to find that info so it's
clearer to document it explicitly here for consistency with the "policy
tests" section below where all the URLs contain a video_id parameter.

Issue: google/ExoPlayer#9852
PiperOrigin-RevId: 421781663

demos/main/src/main/assets/media.exolist.json

@@ -35,31 +35,31 @@
         "name": "HD (cenc)",
         "uri": "https://storage.googleapis.com/wvmedia/cenc/h264/tears/tears.mpd",
         "drm_scheme": "widevine",
-        "drm_license_uri": "https://proxy.uat.widevine.com/proxy?provider=widevine_test"
+        "drm_license_uri": "https://proxy.uat.widevine.com/proxy?video_id=2015_tears&provider=widevine_test"
       },
       {
         "name": "UHD (cenc)",
         "uri": "https://storage.googleapis.com/wvmedia/cenc/h264/tears/tears_uhd.mpd",
         "drm_scheme": "widevine",
-        "drm_license_uri": "https://proxy.uat.widevine.com/proxy?provider=widevine_test"
+        "drm_license_uri": "https://proxy.uat.widevine.com/proxy?video_id=2015_tears&provider=widevine_test"
       },
       {
         "name": "HD (cbcs)",
         "uri": "https://storage.googleapis.com/wvmedia/cbcs/h264/tears/tears_aes_cbcs.mpd",
         "drm_scheme": "widevine",
-        "drm_license_uri": "https://proxy.uat.widevine.com/proxy?provider=widevine_test"
+        "drm_license_uri": "https://proxy.uat.widevine.com/proxy?video_id=2015_tears&provider=widevine_test"
       },
       {
         "name": "UHD (cbcs)",
         "uri": "https://storage.googleapis.com/wvmedia/cbcs/h264/tears/tears_aes_cbcs_uhd.mpd",
         "drm_scheme": "widevine",
-        "drm_license_uri": "https://proxy.uat.widevine.com/proxy?provider=widevine_test"
+        "drm_license_uri": "https://proxy.uat.widevine.com/proxy?video_id=2015_tears&provider=widevine_test"
       },
       {
         "name": "Secure -> Clear -> Secure (cenc)",
         "uri": "https://storage.googleapis.com/exoplayer-test-media-1/widevine/tears_enc_clear_enc.mpd",
         "drm_scheme": "widevine",
-        "drm_license_uri": "https://proxy.uat.widevine.com/proxy?provider=widevine_test",
+        "drm_license_uri": "https://proxy.uat.widevine.com/proxy?video_id=2015_tears&provider=widevine_test",
         "drm_session_for_clear_content": true
       }
     ]
@@ -71,25 +71,25 @@
         "name": "HD (cenc, full-sample)",
         "uri": "https://storage.googleapis.com/wvmedia/cenc/vp9/tears/tears.mpd",
         "drm_scheme": "widevine",
-        "drm_license_uri": "https://proxy.uat.widevine.com/proxy?provider=widevine_test"
+        "drm_license_uri": "https://proxy.uat.widevine.com/proxy?video_id=2015_tears&provider=widevine_test"
       },
       {
         "name": "UHD (cenc, full-sample)",
         "uri": "https://storage.googleapis.com/wvmedia/cenc/vp9/tears/tears_uhd.mpd",
         "drm_scheme": "widevine",
-        "drm_license_uri": "https://proxy.uat.widevine.com/proxy?provider=widevine_test"
+        "drm_license_uri": "https://proxy.uat.widevine.com/proxy?video_id=2015_tears&provider=widevine_test"
       },
       {
         "name": "HD (cenc, sub-sample)",
         "uri": "https://storage.googleapis.com/wvmedia/cenc/vp9/subsample/24fps/tears/tears.mpd",
         "drm_scheme": "widevine",
-        "drm_license_uri": "https://proxy.uat.widevine.com/proxy?provider=widevine_test"
+        "drm_license_uri": "https://proxy.uat.widevine.com/proxy?video_id=2015_tears&provider=widevine_test"
       },
       {
         "name": "UHD (cenc, sub-sample)",
         "uri": "https://storage.googleapis.com/wvmedia/cenc/vp9/subsample/24fps/tears/tears_uhd.mpd",
         "drm_scheme": "widevine",
-        "drm_license_uri": "https://proxy.uat.widevine.com/proxy?provider=widevine_test"
+        "drm_license_uri": "https://proxy.uat.widevine.com/proxy?video_id=2015_tears&provider=widevine_test"
       }
     ]
   },
@@ -100,13 +100,13 @@
         "name": "HD (cenc)",
         "uri": "https://storage.googleapis.com/wvmedia/cenc/hevc/tears/tears.mpd",
         "drm_scheme": "widevine",
-        "drm_license_uri": "https://proxy.uat.widevine.com/proxy?provider=widevine_test"
+        "drm_license_uri": "https://proxy.uat.widevine.com/proxy?video_id=2015_tears&provider=widevine_test"
       },
       {
         "name": "UHD (cenc)",
         "uri": "https://storage.googleapis.com/wvmedia/cenc/hevc/tears/tears_uhd.mpd",
         "drm_scheme": "widevine",
-        "drm_license_uri": "https://proxy.uat.widevine.com/proxy?provider=widevine_test"
+        "drm_license_uri": "https://proxy.uat.widevine.com/proxy?video_id=2015_tears&provider=widevine_test"
       }
     ]
   },