Accept other kwargs for file upload task

[jawnsy]

The file upload task does not provide a content_type variable:

prefect-gcp/prefect_gcp/cloud_storage.py

Line 279 in 378ac3e

async def cloud_storage_upload_blob_from_file(

Hence, it relies on the default behavior of Google Cloud SDK's MIME type detection, and cannot be overridden: https://googleapis.dev/python/storage/latest/storage/blobs.html#google.cloud.storage.blob.Blob.upload_from_filename

The above documentation says that this method's MIME type detection works as follows:

Upload this blob’s contents from the content of a named file.

The content type of the upload will be determined in order of precedence:

• The value passed in to this method (if not None)
• The value stored on the current blob
• The value given by mimetypes.guess_type
• The default value (‘application/octet-stream’)