Add base mainnet chain selector (#231)

* Add base mainnet chain selector

* Auto-fix: buf format, gofmt, go generate, go mod tidy

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Co-authored-by: app-token-issuer-engops[bot] <144731339+app-token-issuer-engops[bot]@users.noreply.github.com>

Author: ilija42

cre/capabilities/blockchain/evm/v1alpha/client.proto

@@ -201,6 +201,10 @@ service Client {
               key: "ethereum-testnet-sepolia"
               value: 16015286601757825753
             },
+            {
+              key: "ethereum-mainnet-base-1"
+              value: 15971525489660198786
+            },
             {
               key: "ethereum-testnet-sepolia-base-1"
               value: 10344971235874465080