fix(storage, windows): Reference.putData does not work as expected on Windows

[espresso3389]

Description

Reference.putData writes some garbage on Firebase Storage.

The reason behind the issue is that:

• FirebaseStoragePlugin::ReferencePutData/FirebaseStoragePlugin::ReferencePutString passes wrong byte sequence/size to PutDataStreamHandler
• PutDataStreamHandler does not keep the actual data but just a dangling pointer

Related Issues

Checklist

For Windows, there seems almost no tests. How should I start testing with the current situation???

• I read the [Contributor Guide] and followed the process outlined there for submitting PRs.
• My PR includes unit or integration tests for all changed/updated/fixed behaviors (See [Contributor Guide]).
• All existing and new tests are passing.
• I updated/added relevant documentation (doc comments with ///).
• The analyzer (melos run analyze) does not report any problems on my PR.
• I read and followed the [Flutter Style Guide].
• I signed the [CLA].
• I am willing to follow-up on review comments in a timely manner.

Breaking Change

Does your PR require plugin users to manually update their apps to accommodate your change?

• Yes, this is a breaking change.
• No, this is not a breaking change.

[russellwheatley]

@espresso3389 - Thank you for this. Could you merge this with master and we can look to to get this merged?

We don't currently have integration tests for Windows storage as their is no emulator available on the C++ SDK. We make it clear on the README windows is not production ready.

[espresso3389]

@russellwheatley I've merged the latest master commit. Could you take a look?

[russellwheatley]

Hey @espresso3389 - there's quite a few things I found not working as intended on Storage windows and I'm going to be fixing them and adding e2e tests 🤞 (Going to use live Firebase project). It is work in progress but here is my PR if you want to track progress: #12723

Thank you for bringing this issue to my attention!