Add ledger range to getHealth endpoint

[2opremio]

What

Add first and last known ledger sequences to the getHealth method response

Why

Enable health probes to make decisions based on the ingested range

Known limitations

N/A

[sreuland]

lgtm!

[2opremio]

I am not sure why the system tests are failing :S

  Scenario Outline: DApp developer compiles, installs, deploys and invokes a contract                                                     # ./dapp_develop.feature:5
soroban-rpc  | time="2024-04-11T21:05:01.599Z" level=info msg="Ledger: Got consensus: [seq=51, prev=afc03f, txs=0, ops=0, sv: [ SIGNED@local_core txH: dc0637, ct: 1712869501, upgrades: [ ] ]]" pid=321 subservice=stellar-core
soroban-rpc  | time="2024-04-11T21:05:01.600Z" level=info msg="Bucket: BucketIndex::createIndex() indexing individual keys in bucket buckets/tmp/bucket-e83e7137ed77b66f/tmp-bucket-193f0d601519b981.xdr" pid=321 subservice=stellar-core
soroban-rpc  | time="2024-04-11T21:05:01.603Z" level=info msg="Ledger: Closed ledger: [seq=51, hash=0f6839]" pid=321 subservice=stellar-core
soroban-rpc  | time="2024-04-11T21:05:01.605Z" level=info msg="Ingesting ledger 52" pid=321
soroban-rpc  | time="2024-04-11T21:05:02.285Z" level=info msg="starting request" host="localhost:8000" ip="127.0.0.1:43840" method=POST path=/ pid=321 req=e579883f90f8/quDknYtUfI-000015 subsys=http useragent=Go-http-client/1.1
soroban-rpc  | time="2024-04-11T21:05:02.285Z" level=info msg="starting JSONRPC request" json_req=8 method=getLedgerEntries pid=321 req=16 subsys=jsonrpc
running command soroban [contract install --wasm ./test_tmp_workspace/soroban_examples/hello_world/target/wasm32-unknown-unknown/release/soroban_hello_world_contract.wasm --rpc-url http://localhost:8000/soroban/rpc --source SC5O7VZUXDJ6JBDSZ74DSERXL7W3Y5LTOAMRF7RQRL3TAGAPS7LUVG3L --network-passphrase Standalone Network ; February 2017] 

error: jsonrpc error: Parse error: missing field `type` at line 1 column 1187
running command rm [-rf test_tmp_workspace] 

[2opremio]

I am thinking maybe stellar/stellar-cli#1281 caused it, but I don't know how

[2opremio]

OK, I think I know what happened ( 🤦 #134 ). However, the system test logs are not very helpful since, for some, reason the soroban_rpc logs don't contain the offending simulateTransaction request and response (CC @sreuland )