[twitter] ignore 'Unavailable' media (#5736)

… including geo-restricted content.

add 'unavailable' option to allow re-enabling them again

test/results/twitter.py

@@ -621,6 +621,14 @@ The Washington Post writes, "Three weeks after the toxic train derailment in Ohi
     "content"  : "Biden wants to replace lead pipes. He failed to mention that the unfunded mandate sets an almost impossible timeline, will cost billions, infringe on the rights of the States and their residents – all for benefits that may be entirely speculative. #sotu https://ag.ks.gov/media-center/news-releases/2024/02/09/kobach-leads-coalition-demanding-biden-drop-unnecessary-epa-rule",
 },
 
+{
+    "#url"     : "https://x.com/jsports_motor/status/1801338077618524583",
+    "#comment" : "geo-restricted video (#5736)",
+    "#category": ("", "twitter", "tweet"),
+    "#class"   : twitter.TwitterTweetExtractor,
+    "#count"   : 0,
+},
+
 {
     "#url"     : "https://twitter.com/playpokemon/status/1263832915173048321/quotes",
     "#category": ("", "twitter", "quotes"),