fix: enhance owner and username checks to prevent empty string handling in AuthorUrl

Author: uzulla

src/Adapters/Gist/Detectors/AuthorUrl.php

@@ -16,7 +16,7 @@ public function detect(): ?UriInterface
         $api = $extractor->getApi();
         $owner = $api->str('owner');
 
-        if ($owner !== null) {
+        if ($owner !== null && $owner !== '') {
             return $extractor->getCrawler()->createUri("https://github.com/{$owner}");
         }
 

src/Adapters/ImageShack/Detectors/AuthorUrl.php

@@ -16,7 +16,7 @@ public function detect(): ?UriInterface
         $api = $extractor->getApi();
         $owner = $api->str('owner', 'username');
 
-        if ($owner !== null) {
+        if ($owner !== null && $owner !== '') {
             return $extractor->getCrawler()->createUri("https://imageshack.com/{$owner}");
         }
 

src/Adapters/Twitter/Detectors/AuthorUrl.php

@@ -16,7 +16,7 @@ public function detect(): ?UriInterface
         $api = $extractor->getApi();
         $username = $api->str('includes', 'users', '0', 'username');
 
-        if ($username !== null) {
+        if ($username !== null && $username !== '') {
             return $extractor->getCrawler()->createUri("https://twitter.com/{$username}");
         }