Handle unmounted state in NetworkContext (#53)

Add early return for unmounted component in NetworkContext.

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## Summary by CodeRabbit

* **Bug Fixes**
* Improved component initialization timing to ensure proper rendering
sequencing in the network provider.

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settings.</sub>

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Author: techrebelgit

src/contexts/NetworkContext.tsx

@@ -28,6 +28,8 @@ export function NetworkProvider({ children }: NetworkProviderProps) {
     }
   }, []);
 
+    if (!mounted) return null; 
+
   const setNetwork = (network: NetworkType) => {
     setCurrentNetwork(network);
     safeLocalStorage.setItem('escrow-viewer-network', network);