Implement override to force engine-api in the absence of TTD

[garyschulte]

Description

In order to smooth the preparations for the merge, consensus is that we want execution clients to enable the engine API even in the absence of merge parameters. This is in essence a re-enabling of the --engine-rpc-enabled api flag removed in #3875

Acceptance Criteria

• make the engine-api available in the absence of merge configs
• ensure rational behavior pre-TTD calls to engine api endpoints

[MysticRyuujin]

I just pulled the latest develop docker image and I'm getting this trying to run on mainnet. The error seems to happen every time my Lighthouse node tries to talk to it:

2022-08-01 22:04:40.021+00:00 | vert.x-eventloop-thread-1 | ERROR | ExecutionEngineJsonRpcMethod | failed to exec consensus method engine_exchangeTransitionConfigurationV1
java.util.NoSuchElementException: No value present
	at java.base/java.util.Optional.get(Optional.java:148)
	at org.hyperledger.besu.ethereum.api.jsonrpc.internal.methods.engine.EngineExchangeTransitionConfiguration.syncResponse(EngineExchangeTransitionConfiguration.java:85)
	at org.hyperledger.besu.ethereum.api.jsonrpc.internal.methods.ExecutionEngineJsonRpcMethod.lambda$response$0(ExecutionEngineJsonRpcMethod.java:67)
	at io.vertx.core.impl.ContextImpl.lambda$null$0(ContextImpl.java:159)
	at io.vertx.core.impl.AbstractContext.dispatch(AbstractContext.java:100)
	at io.vertx.core.impl.ContextImpl.lambda$executeBlocking$1(ContextImpl.java:157)
	at io.vertx.core.impl.TaskQueue.run(TaskQueue.java:76)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
	at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
	at java.base/java.lang.Thread.run(Thread.java:829)

[non-fungible-nelson]

Reopening for above bug - can re-close with investigation @garyschulte