Update elections-phragmen weight to WeightInfo (#7161)

* Update elections-phragmen weight to WeightInfo

* Fix benchmark tests

* Update weights

* Update test

* Update another thest :"

* Weights from benchmarking machine

./substrate2/target/release/substrate benchmark --chain dev --steps 50 --repeat 20 --pallet pallet_elections_phragmen --extrinsic "*" --raw --execution=wasm --wasm-execution=compiled --output

* Update weights from the benchmarking machine

* Fix tests one last time

Co-authored-by: Shawn Tabrizi <[email protected]>