Merge pull request #56653 from nextcloud/backport/55981/stable31

[stable31] fix(encryption): Increment `lastChunkNr` when size is off

Author: artonge

lib/private/Files/Storage/Wrapper/Encryption.php

@@ -464,6 +464,7 @@ protected function fixUnencryptedSize(string $path, int $size, int $unencryptedS
 			if (strlen($lastChunkContentEncrypted) > $blockSize) {
 				$newUnencryptedSize += $unencryptedBlockSize;
 				$lastChunkContentEncrypted = substr($lastChunkContentEncrypted, $blockSize);
+				$lastChunkNr++;
 			}
 		}