Syncing signed collections stores signatures as bytes

[newswangerd]

Version
pulcore 3.21
pulp_ansible 0.15

Describe the bug
Signatures loaded during syncs are saved as bytes.

To Reproduce
Sync a signed collection. The signature shows up a b'' string on the API:

            "signature": "b'-----BEGIN PGP SIGNATURE-----\\nVersion: GnuPG v1\\n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\\nsjd1+WBrGTw=\\n=WIPN\\n-----END PGP SIGNATURE-----\\n'",
            "pubkey_fingerprint": "39B5D759361A97464C564A8FE1A4BD708A828AAD",

Expected behavior
The signature should be a regular string