fix: update soneium explorer URL (#486)

### Description

fix: update soneium explorer URL

### Backward compatibility

<!--
Are these changes backward compatible? Note that additions are backwards
compatible.

Yes/No
-->

### Testing

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Have any new metadata configs and deployment addresses been used with
any Hyperlane tooling, such as the CLI?
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.changeset/sour-rules-hammer.md

@@ -0,0 +1,5 @@
+---
+'@hyperlane-xyz/registry': patch
+---
+
+Update soneium block explorer.

chains/soneium/metadata.yaml

@@ -1,9 +1,9 @@
 # yaml-language-server: $schema=../schema.json
 blockExplorers:
-  - apiUrl: https://explorer.soneium.org/api
+  - apiUrl: https://soneium.blockscout.com/api
     family: blockscout
     name: Soneium Explorer
-    url: https://explorer.soneium.org
+    url: https://soneium.blockscout.com
 blocks:
   confirmations: 1
   estimateBlockTime: 2