Close #8904 Use the gecko fetch client when resuming a download

[Amejia481]

Before adding the new gecko view download API. We used to use the gecko fetch client that has the corresponding header for performing the resuming download. Now that we are always using the new API when available, resuming downloads are failing, as the new gv download API doesn't allow to pass headers we have to use the gecko fetch client when performing a resuming a download. Related issue mozilla-mobile/fenix#9354

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After merge

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• Breaking Changes: If this is a breaking change, please push a draft PR on Reference Browser to address the breaking issues.

[csadilek]

👍