feat: add principal cache etag to account endpoints #2510

Job	Run time
lint	1m 5s
test (api)	9m 30s
test (bns)	3m 1s
test (bns-e2e)	6m 59s
test (btc-faucet)	1m 24s
test-2_5 (block-zero-handling)	1m 21s
test (event-replay)	1m 53s
test-2_5 (faucet-stx)	1m 22s
test (rpc)	1m 28s
test-2_5 (pox-4-btc-address-formats)	2m 12s
test-2_5 (pox-4-delegate-aggregation)	2m 4s
test-2_5 (pox-4-delegate-stacking)	1m 56s
test-2_5 (pox-4-delegate-revoked-stacking)	2m 8s
test-2_5 (pox-4-stack-extend-increase)	2m 3s
test-rosetta (rosetta)	2m 53s
test-2_5 (pox-4-rosetta-btc-addr-types)	4m 38s
test-rosetta (rosetta-construction)	2m 21s
test-2_5 (pox-4-rosetta-cycle-phases)	1m 16s
test-rosetta (rosetta-cli-data)	2m 19s
test-2_5 (pox-4-rosetta-segwit)	1m 35s
test-rosetta (rosetta-cli-construction)	2m 35s
test-2_5 (pox-4-burnchain-stack-stx)	1m 30s
test-2_5 (pox-4-burnchain-delegate-stx)	1m 26s
build-publish	1m 55s
	1h 0m 54s

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