Micro-services fight for signing credentials

Launching the various services that attach to the authority agent in unison sometimes fails thus:

```
webhook-1 | Connecting to holochain admin websocket
webhook-1 | Authorising holochain signing credentials
webhook-1 | internal_error: Attempted to commit a bundle to the source chain, but the source chain head has moved since the bundle began. Bundle head: Some(ActionHash(uhCkk8fmCFQ7vBdiPLz55POx89glTz18QQRje1IeyhzEMQai_nyrN)), Current head: Some(HeadInfo { action: ActionHash(uhCkkitzgg5Vwt70TzOq5OtsGCejNXhaCUm8VIr3j1pTath3qTpeu), seq: 5, timestamp: Timestamp(2024-08-01T08:51:23.665075Z) })
webhook-1 | at catchError (file:///home/node/node_modules/@holochain/client/lib/api/common.js:37:23)
external-id-attestor-1 | internal_error: Attempted to commit a bundle to the source chain, but the source chain head has moved since the bundle began. Bundle head: Some(ActionHash(uhCkk8fmCFQ7vBdiPLz55POx89glTz18QQRje1IeyhzEMQai_nyrN)), Current head: Some(HeadInfo { action: ActionHash(uhCkkitzgg5Vwt70TzOq5OtsGCejNXhaCUm8VIr3j1pTath3qTpeu), seq: 5, timestamp: Timestamp(2024-08-01T08:51:23.665075Z) })
webhook-1 | at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
external-id-attestor-1 | at catchError (file:///home/node/node_modules/@holochain/client/lib/api/common.js:37:23)
webhook-1 | at async AdminWebsocket.grantZomeCallCapability (file:///home/node/node_modules/@holochain/client/lib/api/common.js:13:22)
external-id-attestor-1 | at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
webhook-1 | at async AdminWebsocket.grantSigningKey (file:///home/node/node_modules/@holochain/client/lib/api/admin/websocket.js:143:9)
external-id-attestor-1 | at async AdminWebsocket.grantZomeCallCapability (file:///home/node/node_modules/@holochain/client/lib/api/common.js:13:22)
webhook-1 | at async AdminWebsocket.authorizeSigningCredentials (file:///home/node/node_modules/@holochain/client/lib/api/admin/websocket.js:168:27)
external-id-attestor-1 | at async AdminWebsocket.grantSigningKey (file:///home/node/node_modules/@holochain/client/lib/api/admin/websocket.js:143:9)
external-id-attestor-1 | at async AdminWebsocket.authorizeSigningCredentials (file:///home/node/node_modules/@holochain/client/lib/api/admin/websocket.js:168:27)
external-id-attestor-1 | at async runExternalIdAttestorFromEnv (file:///home/node/node_modules/@holoom/authority/dist/index.node.js:144:5)
```

The micro-services need some retry or coordination strategy to address this, else manual restarts are required.

More generally, it would be useful to solve this problem for all commit types that happen not just on launch but in operation too.