bump to polkadot-stable2407-3

[clangenb]

Changes:

• Treasury pallet: this one only removed already unused parameters and dispatches - no functional change.
• Bump rust toolchain to stable 1.81.0, which is the one that parity uses

Notes:

• I had to downgrade a few crates after running psvm polkadot-stable2407-3 because they seem to have forgotten to vendor them after the patch, see parachain build error with polkadot-stable2407-3, as patched crates are missing vendoring paritytech/polkadot-sdk#6185
• Due to a minor incompatibility, I also had to downgrade sp-consensus-beefy with cargo update -p sp-consensus-beefy --precise 22.0.0 to fix the rococo-runtime build.

Tests:

• Checked that the updated binary produces blocks locally