Don't try to follow remote item from non-URI or scheme-less URI

- Address https://github.com/friendica/friendica/issues/12486#issuecomment-1407679388
- Address https://github.com/friendica/friendica/issues/12486#issuecomment-1433112562

src/Module/Contact/Follow.php

@@ -40,6 +40,7 @@ use Friendica\Network\HTTPException\ForbiddenException;
 use Friendica\Network\Probe;
 use Friendica\Util\Profiler;
 use Friendica\Util\Strings;
+use GuzzleHttp\Psr7\Uri;
 use Psr\Log\LoggerInterface;
 
 class Follow extends BaseModule
@@ -223,6 +224,12 @@ class Follow extends BaseModule
 
 	protected function followRemoteItem(string $url)
 	{
+		try {
+			$uri = new Uri($url);
+			if (!$uri->getScheme()) {
+				return;
+			}
+
 			$itemId = Item::fetchByLink($url, $this->session->getLocalUserId());
 			if (!$itemId) {
 				// If the user-specific search failed, we search and probe a public post
@@ -235,5 +242,8 @@ class Follow extends BaseModule
 					$this->baseUrl->redirect('display/' . $item['guid']);
 				}
 			}
+		} catch (\InvalidArgumentException $e) {
+			return;
+		}
 	}
 }