mft cp command with OVH S3 buckets

**Describe the bug**
I try to copy a file from an S3 storage to another S3 storage. Both buckets are hosted on [OVH](https://www.ovhcloud.com/en/public-cloud/object-storage/) provider.
`mft ls storage-name` works and lists the objects present in the source and destination bucket.
`mft cp storage-name1/file.txt storage-name2/` command creates a file on the destination bucket, but size is zero.
`mft cp` command output:
```
user@mft-master-01:~$ mft cp blaze-test-s3-gra/hello.txt blaze-test-02-s3-gra/
Total number of 1 files to be transferred. Total volume is 6 bytes. Do you want to start the transfer? [Y/n]: y
[------------------------------------] 0%
local variable 'prev_percentage' referenced before assignment
```
There are some errors in airava.log file:
```
2023-08-24 12:44:08,960 [pool-9-thread-20] WARN com.amazonaws.services.s3.internal.S3AbortableInputStream {} - Not all bytes were read from the S3ObjectInputStream, aborting HTTP connection. This is likely an error and may result in sub-optimal behavior. Request only the bytes you need via a ranged GET or drain the input stream after use.
2023-08-24 12:44:08,989 [pool-9-thread-20] WARN com.amazonaws.services.s3.internal.S3AbortableInputStream {} - Not all bytes were read from the S3ObjectInputStream, aborting HTTP connection. This is likely an error and may result in sub-optimal behavior. Request only the bytes you need via a ranged GET or drain the input stream after use.
2023-08-24 12:44:08,989 [pool-9-thread-20] WARN com.amazonaws.services.s3.internal.S3AbortableInputStream {} - Not all bytes were read from the S3ObjectInputStream, aborting HTTP connection. This is likely an error and may result in sub-optimal behavior. Request only the bytes you need via a ranged GET or drain the input stream after use.
2023-08-24 12:44:08,989 [pool-7-thread-8] ERROR org.apache.airavata.mft.transport.s3.S3OutgoingConnector {} - S3 failed to upload chunk to bucket blaze-test-02-s3-gra for resource path hello.txt
2023-08-24 12:44:08,990 [pool-7-thread-8] ERROR org.apache.airavata.mft.agent.TransportMediator {} - Transfer 9abb6f6c-7a06-4ed9-89cf-81bee0e7682b failed with error
java.lang.NullPointerException: null
at org.apache.airavata.mft.transport.s3.S3OutgoingConnector.complete(S3OutgoingConnector.java:134) ~[?:?]
at org.apache.airavata.mft.agent.TransportMediator.transferSingleThread(TransportMediator.java:149) ~[mft-agent-service-0.01-SNAPSHOT.jar:0.01-SNAPSHOT]
at org.apache.airavata.mft.agent.TransferOrchestrator.processTransfer(TransferOrchestrator.java:187) ~[mft-agent-service-0.01-SNAPSHOT.jar:0.01-SNAPSHOT]
at org.apache.airavata.mft.agent.TransferOrchestrator.lambda$submitTransferToProcess$0(TransferOrchestrator.java:101) ~[mft-agent-service-0.01-SNAPSHOT.jar:0.01-SNAPSHOT]
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515) [?:?]
at java.util.concurrent.FutureTask.run(FutureTask.java:264) [?:?]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) [?:?]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) [?:?]
at java.lang.Thread.run(Thread.java:829) [?:?]
2023-08-24 12:44:08,995 [OkHttp http://localhost:8500/...] INFO org.apache.airavata.mft.controller.MFTController {} - Received state Key 9abb6f6c-7a06-4ed9-89cf-81bee0e7682b/local-agent/da256772-ae53-4cfa-a2b0-a71550defc19/0b8c6f040a1cdf526b05508a3bee7a10/1692881048992 val {"state":"FAILED","publisher":"local-agent","updateTimeMils":1692881048992,"percentage":0.0,"description":"Transfer failed due to java.lang.NullPointerException\n\tat org.apache.airavata.mft.transport.s3.S3OutgoingConnector.complete(S3OutgoingConnector.java:134)\n\tat org.apache.airavata.mft.agent.TransportMediator.transferSingleThread(TransportMediator.java:149)\n\tat org.apache.airavata.mft.agent.TransferOrchestrator.processTransfer(TransferOrchestrator.java:187)\n\tat org.apache.airavata.mft.agent.TransferOrchestrator.lambda$submitTransferToProcess$0(TransferOrchestrator.java:101)\n\tat java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)\n\tat java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)\n\tat java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)\n\tat java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)\n\tat java.base/java.lang.Thread.run(Thread.java:829)\n","childId":null}
2023-08-24 12:44:08,996 [OkHttp http://localhost:8500/...] INFO org.apache.airavata.mft.admin.MFTConsulClient {} - Saved transfer status {"state":"FAILED","publisher":"local-agent","updateTimeMils":1692881048992,"percentage":0.0,"description":"Transfer failed due to java.lang.NullPointerException\n\tat org.apache.airavata.mft.transport.s3.S3OutgoingConnector.complete(S3OutgoingConnector.java:134)\n\tat org.apache.airavata.mft.agent.TransportMediator.transferSingleThread(TransportMediator.java:149)\n\tat org.apache.airavata.mft.agent.TransferOrchestrator.processTransfer(TransferOrchestrator.java:187)\n\tat org.apache.airavata.mft.agent.TransferOrchestrator.lambda$submitTransferToProcess$0(TransferOrchestrator.java:101)\n\tat java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)\n\tat java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)\n\tat java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)\n\tat java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)\n\tat java.base/java.lang.Thread.run(Thread.java:829)\n","childId":"0b8c6f040a1cdf526b05508a3bee7a10"}
2023-08-24 12:44:08,996 [OkHttp http://localhost:8500/...] INFO org.apache.airavata.mft.controller.MFTController {} - Deleting key mft/controller/messages/states/9abb6f6c-7a06-4ed9-89cf-81bee0e7682b/local-agent/da256772-ae53-4cfa-a2b0-a71550defc19/0b8c6f040a1cdf526b05508a3bee7a10/1692881048992
2023-08-24 12:44:08,996 [pool-7-thread-8] INFO org.apache.airavata.mft.agent.TransferOrchestrator {} - Removed transfer 9abb6f6c-7a06-4ed9-89cf-81bee0e7682b from queue with transfer success = false. Total running 13
```

**To Reproduce**
Create 2 storages of type S3 (OVH provider endpoint) with `mft storage add`.
Run command:
` mft cp storage-name1/file.txt storage-name2/`

**Expected behavior**
The file should be present on the destination storage with the same size of the source file.

**Screenshots**
If applicable, add screenshots to help explain your problem.

**Additional context**
Add any other context about the problem here.

Reproduce the transfer with two OVH S3 storages using the `mft cp` command, then inspect `S3OutgoingConnector.complete` at line 134 and the surrounding transfer flow in `TransportMediator`. Done means the destination object contains the source bytes and size, the transfer completes without a NullPointerException, and the command no longer reports the uninitialized progress variable.

Written by the indexing model from the issue text.