feat(build): add Solana feature flag (#3923)

# Motivation

We start the integration of Solana creating a feature flag to enable or
disabled the access to Solana network.

.github/workflows/deploy-to-environment.yml

@@ -94,6 +94,7 @@ jobs:
             echo "VITE_ETHERSCAN_API_KEY=${{ secrets.VITE_ETHERSCAN_API_KEY_STAGING }}" >> $GITHUB_ENV
             echo "VITE_INFURA_API_KEY=${{ secrets.VITE_INFURA_API_KEY_STAGING }}" >> $GITHUB_ENV
             echo "VITE_ALCHEMY_API_KEY=${{ secrets.VITE_ALCHEMY_API_KEY_STAGING }}" >> $GITHUB_ENV
+            echo "VITE_SOLANA_NETWORK_ENABLED=${{ secrets.VITE_SOLANA_NETWORK_ENABLED_STAGING }}" >> $GITHUB_ENV
             echo "VITE_WALLET_CONNECT_PROJECT_ID=${{ secrets.VITE_WALLET_CONNECT_PROJECT_ID_STAGING }}" >> $GITHUB_ENV
             echo "VITE_AIRDROP=${{ secrets.VITE_AIRDROP_STAGING }}" >> $GITHUB_ENV
             echo "VITE_AIRDROP_COMPLETED=${{ secrets.VITE_AIRDROP_COMPLETED_STAGING }}" >> $GITHUB_ENV
@@ -122,6 +123,7 @@ jobs:
             echo "VITE_ETHERSCAN_API_KEY=${{ secrets.VITE_ETHERSCAN_API_KEY_BETA }}" >> $GITHUB_ENV
             echo "VITE_INFURA_API_KEY=${{ secrets.VITE_INFURA_API_KEY_BETA }}" >> $GITHUB_ENV
             echo "VITE_ALCHEMY_API_KEY=${{ secrets.VITE_ALCHEMY_API_KEY_BETA }}" >> $GITHUB_ENV
+            echo "VITE_SOLANA_NETWORK_ENABLED=${{ secrets.VITE_SOLANA_NETWORK_ENABLED_BETA }}" >> $GITHUB_ENV
             echo "VITE_WALLET_CONNECT_PROJECT_ID=${{ secrets.VITE_WALLET_CONNECT_PROJECT_ID_BETA }}" >> $GITHUB_ENV
             echo "VITE_OISY_URL=${{ secrets.VITE_OISY_URL_BETA }}" >> $GITHUB_ENV
             echo "VITE_AIRDROP=${{ secrets.VITE_AIRDROP_BETA }}" >> $GITHUB_ENV

src/frontend/src/env/networks.sol.env.ts

@@ -0,0 +1,3 @@
+// TODO: to be removed when the feature is fully implemented
+export const SOLANA_NETWORK_ENABLED =
+	JSON.parse(import.meta.env.VITE_SOLANA_NETWORK_ENABLED ?? false) === true;