fix: improve error handling for TUS upload recovery

- Added explicit handling of IOException during TUS upload offset recovery
- Propagate IOException to caller instead of catching and returning null
- Maintains existing behavior of returning null for other error types

Author: zerox80

opencloudApp/src/main/java/eu/opencloud/android/workers/TusUploadHelper.kt

@@ -244,6 +244,9 @@ class TusUploadHelper(
             }
         } catch (recoverError: Throwable) {
             Timber.w(recoverError, "TUS: recover offset failed")
+            if (recoverError is java.io.IOException) {
+                throw recoverError
+            }
             null
         }