_async_initiate_upload leads to unnecessary storage transactions and Failure metrics

[OliverKleinBST]

In _async_initiate_upload the code tries to delete a blob before upload.
This leads to several effects.

1. if a blob does not exist we get a ResoureNotFoundError, if we have no delete rights we get a HttpResponseError. Those errors will show up as unexpected Failures in the "Insights" Failure metric of the storage account.
2. The delete blob, even if only a trial, leads to additional storage transactions and cost
3. delete_blob should not be required, as storage could be done using the overwrite=True flag leading to the same behavior

Here the problematic code

    async def _async_initiate_upload(self, **kwargs):
        """Prepare a remote file upload"""
        self._block_list = []
        if self.mode == "wb":
            try:
                await self.container_client.delete_blob(self.blob)
            except ResourceNotFoundError:
                pass
            except HttpResponseError:
                pass
            else:
                await self._reinitiate_async_upload()