UTF-8 vs current code page inconsistency

**Describe the bug**
When I download a file using `BlockBlobClient::DownloadTo`, I need to convert `CString` to `std::string` using `CP_UTF8` in `CW2A` call which is expected. However If want to upload a file using `UploadFrom` then the filename must not be in UTF-8 but in current code page (no page specified in `CW2A`.

***Exception or Stack Trace***
When I upload a file, I get an error during the call so convert back the filename to a wide filename if it contains accentuated characters.

**To Reproduce**
Call those functions with accentuated filename coming from `CString` object.

***Code Snippet***
```
void ReadBlob(const CString &fileName, const CString &blobName)
{
const std::string blobNameUtf8(CW2A(blobName.GetString(), CP_UTF8));
const std::string filename(CW2A(fileName.GetString(), CP_UTF8)); // *** Must have CP_UTF8 here

BlockBlobClient blockBlob = m_ContainerClient->GetBlockBlobClient(blobNameUtf8);

blockBlob.DownloadTo(filename);
}

void WriteBlob(const CString &fileName, const CString &blobName)
{
const std::string blobNameUtf8(CW2A(blobName.GetString(), CP_UTF8));
const std::string filename(CW2A(fileName.GetString())); // *** Must NOT have CP_UTF8 here

BlockBlobClient blockBlob = m_ContainerClient->GetBlockBlobClient(blobNameUtf8);

blockBlob.DeleteIfExists();
blockBlob.UploadFrom(filename);
}

```
**Expected behavior**
Consistent use of UTF-8 in API.

**Screenshots**
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**Setup (please complete the following information):**
- OS: Windows 11
- IDE : Visual Studio 2022
- Version of the Library used 1.12.0 and 1.15.0

**Additional context**
With incorrect encoding, operation on file fails when filename contains accentuated characters.

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