CI: Upgrade rust compiler for E2E tests

[zyzniewski-reef]

*** Building substrate binary...
error: failed to parse manifest at /home/runner/work/bittensor/bittensor/subtensor/Cargo.toml
Caused by:
feature edition2024 is required
The package requires the Cargo feature called edition2024, but that feature is not stabilized in this version of Cargo (1.84.1 (66221abde 2024-11-19)).
Consider trying a newer version of Cargo (this may require the nightly release).
See https://doc.rust-lang.org/nightly/cargo/reference/unstable.html#edition-2024 for more information about the status of this feature.

[thewhaleking]

I'm good with this, but I do want Cameron to take a look aswell @camfairchild