Add http1 feature to hyper-util

[Serock3]

Fixes crash when legacy hyper client tries to use http1, by enabling the feature in hyper-util.

Normally. we promote http1.1 connections to http2 using Application-Layer Protocol Negotiation (ALPN). This behavior seems to not be reliable, as seen in this test run
https://github.com/mullvad/mullvadvpn-app/actions/runs/11438592659/job/31820684203

which paniced with the following error message:

thread 'tokio-runtime-worker' panicked at /Users/mullemullvad/.cargo/registry/src/index.crates.io-6f17d22bba15001f/hyper-util-0.1.9/src/client/legacy/client.rs:607:37:
http1 feature is not enabled
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
/Users/mullemullvad/actions-runner/_work/mullvadvpn-app/mullvadvpn-app/ios/MullvadVPNUITests/Networking/MullvadAPIWrapper.swift:114: error: -[MullvadVPNUITests.AccountTests testCreateAccount] : failed - Failed to delete account with error: The operation couldn’t be completed. (MullvadVPNUITests.ApiError error 1.)

Passing test run: https://github.com/mullvad/mullvadvpn-app/actions/runs/11440284762

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This change is 

[linear]

IOS-891 Panic due to missing http1 feature in mullvad-api crate

[buggmagnet]

Reviewed 1 of 1 files at r1, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved