fix(share_plus): avoid iOS 26 share sheet crash for non-image files

Fixes #3784.

Pre-iOS 26 the plugin set LPLinkMetadata.originalURL to a fake file URL
built from a display string (e.g. "DOCX • 500 KB") so the share sheet
would show the file size/extension as a subtitle. iOS 26 tightened
validation of originalURL: when SHSheetActivityItemsManager tries to
fetch link metadata for the bogus URL — reproducible when sharing .docx
files — it crashes with NSArrayM insertObject:atIndex: object cannot be
nil.

Gate the fake-URL trick on iOS < 26. On iOS 26 and later, leave
originalURL unset; the share sheet works without the size subtitle but
no longer crashes.

Author: MohamedAbdallah-14

packages/share_plus/share_plus/ios/share_plus/Sources/share_plus/FPPSharePlusPlugin.m

@@ -247,7 +247,19 @@ - (LPLinkMetadata *)activityViewControllerLinkMetadata:
     }
 
     // https://stackoverflow.com/questions/60563773/ios-13-share-sheet-changing-subtitle-item-description
-    metadata.originalURL = [NSURL fileURLWithPath:description];
+    // The fake file URL above is a long-standing trick used to surface the
+    // file size/extension as a subtitle in the share sheet. iOS 26 introduced
+    // stricter validation of LPLinkMetadata.originalURL: when the share sheet
+    // tries to fetch link metadata (SHSheetActivityItemsManager) for the
+    // bogus URL — for example when sharing .docx files — it crashes with
+    // "*** -[__NSArrayM insertObject:atIndex:]: object cannot be nil".
+    // Skip the fake URL on iOS 26+ and accept the loss of the subtitle in
+    // exchange for not crashing. See issue #3784.
+    if (@available(iOS 26.0, *)) {
+      // Leave metadata.originalURL nil.
+    } else {
+      metadata.originalURL = [NSURL fileURLWithPath:description];
+    }
     if (_mimeType && [_mimeType hasPrefix:@"image/"]) {
       UIImage *image = [UIImage imageWithContentsOfFile:_path];
       metadata.imageProvider = [[NSItemProvider alloc]