Add 'state is not available' as non-retryable for proof lower bound (#821)

opBNB (BSC-derived) returns this error from eth_getProof on pruned
state. Without it in NO_PROOF_ERRORS, RecursiveLowerBound retries
indefinitely and emits the "report it to dshackle devs" warning.
The same string is already non-retryable in the state detector.

src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/EthereumLowerBoundProofDetector.kt

@@ -31,6 +31,7 @@ class EthereumLowerBoundProofDetector(
             "invalid block height", // hyperliquid
             "not supported",
             "evm module does not exist on height",
+            "state is not available", // opbnb / bsc — eth_getProof on pruned state
         )
     }