leeking headers method _stream_download_dict

[benoitlambare]

Describe the bug
The provider's headers are staying in the eodag response.
Consequence : header issues
Example: "Content-Encoding = br" but I never asked to have compressed data
2 times content-disposition (Content-Disposition + content-disposition)

gulty commit -> 6cc222a
Code To Reproduce
Return method _stream_download_dict

Output
Compete output obtained with maximal verbosity.

Environment:

• Python version: python --version
• EODAG version: eodag version

Additional context
Add any other context about the bug here.