Remove E from validator_client types where it's not required #19463

Job	Run time
Check for 'skip-ci' label	1s
lockbud	13m 53s
check-code	13m 56s
check-msrv	5m 16s
target-branch-check	1s
beacon-chain-tests	16m 41s
network-tests	16m 38s
debug-tests-ubuntu	13m 57s
ef-tests-ubuntu	8m 1s
op-pool-tests	15m 42s
release-tests-ubuntu	16m 41s
release-tests-windows	16m 24s
slasher-tests	3m 15s
state-transition-vectors-ubuntu	2m 34s
basic-simulator-ubuntu	15m 47s
cargo-sort	17s
cargo-udeps	7m 26s
cli-check	8m 2s
compile-with-beta-compiler	14m 51s
execution-engine-integration-ubuntu	11m 10s
fallback-simulator-ubuntu	13m 33s
test-suite-success	1s
	3h 34m 7s

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