[Bug] `net_version` change error when switching from `RPC` provider to a Firehose provider

Bug report

Steps:

1. Fresh graph-node start from fresh database with config below. This creates a chain for mainnet with net_version: 1 in the database.

   [general]
   
   [store]
   [store.primary]
   connection = "postgresql://graph-node:let-me-in@localhost:5432/graph-node"
   weight = 1
   pool_size = 10
   
   [chains]
   ingestor = "block_ingestor_node"
   [chains.mainnet]
   shard = "primary"
   protocol = "ethereum"
   provider = [
     { label = "peering", url = "$RPC_NODE", features = [ "archive", "traces" ] },
   ]
   
   [deployment]
   [[deployment.rule]]
   shard = "primary"
   indexers = [ "default" ]
   

2. Stop graph-node instance.

3. Start it back with a Firehose only provider

   [general]
   
   [store]
   [store.primary]
   connection = "postgresql://graph-node:let-me-in@localhost:5432/graph-node"
   weight = 1
   pool_size = 10
   
   [chains]
   ingestor = "block_ingestor_node"
   [chains.mainnet]
   shard = "primary"
   protocol = "ethereum"
   provider = [
     { label = "firehose", details = { type = "firehose", url = "$FIREHOSE_ENDPOINT", token = "$STREAMING_FAST_API_TOKEN", features = [ "compression", "filters" ] }},
   ]
   
   [deployment]
   [[deployment.rule]]
   shard = "primary"
   indexers = [ "default" ]
   

Yields error message Apr 27 16:03:14.931 ERRO the net version for chain mainnet has changed from 1 to 0 since the last time we ran, component: BlockStore.

Weirdly, the network seems to still be configured correctly, so maybe it's more a warning or maybe we should just ignore net_version and keep only genesis_hash check.

Relevant log output

No response

IPFS hash

No response

Subgraph name or link to explorer

No response

Some information to help us out

• Tick this box if this bug is caused by a regression found in the latest release.
• Tick this box if this bug is specific to the hosted service.
• I have searched the issue tracker to make sure this issue is not a duplicate.

OS information

macOS

Start with the BlockStore logic that compares the stored net_version when a chain provider is changed, using the two configuration examples to reproduce the failure. Determine whether the provider switch should preserve the existing network identity or report a warning, then verify the resulting behavior against the existing chain configuration checks.