Chain selectors pick (#1266)

## Motivation


## Solution

---------

Co-authored-by: Kodey Thomas <[email protected]>
Co-authored-by: Rens Rooimans <[email protected]>

.changeset/cool-mirrors-beg.md

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+---
+"chainlink": patch
+---
+
+#added L3X Config

core/chains/evm/config/toml/defaults/Astar_Mainnet.toml

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+ChainID = '592'
+# FinalityTag will be enabled once the custom tag is implemented
+# FinalityTagEnabled = true
+FinalityDepth = 100
+LogPollInterval = '6s'
+
+[GasEstimator]
+EIP1559DynamicFees = false
+PriceMax = '100000 gwei'
+LimitDefault = 8000000

core/chains/evm/config/toml/defaults/Astar_Shibuya.toml

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+ChainID = '81'
+# FinalityTag will be enabled once the custom tag is implemented
+# FinalityTagEnabled = true
+FinalityDepth = 100
+LogPollInterval = '6s'
+
+[GasEstimator]
+EIP1559DynamicFees = false
+PriceMax = '100000 gwei'
+LimitDefault = 8000000

core/chains/evm/config/toml/defaults/L3X_Mainnet.toml

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+ChainID = '12324'
+ChainType = 'arbitrum'
+FinalityTagEnabled = true
+FinalityDepth = 10
+LinkContractAddress = '0x79f531a3D07214304F259DC28c7191513223bcf3'
+# Produces blocks on-demand
+NoNewHeadsThreshold = '0'
+OCR.ContractConfirmations = 1
+LogPollInterval = '10s'
+
+[GasEstimator]
+Mode = 'Arbitrum'
+LimitMax = 1_000_000_000
+# Arbitrum-based chains uses the suggested gas price, so we don't want to place any limits on the minimum
+PriceMin = '0'
+PriceDefault = '0.1 gwei'
+FeeCapDefault = '1000 gwei'
+BumpThreshold = 5

core/chains/evm/config/toml/defaults/L3X_Sepolia.toml

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+ChainID = '12325'
+ChainType = 'arbitrum'
+FinalityTagEnabled = true
+FinalityDepth = 10
+LinkContractAddress = '0xa71848C99155DA0b245981E5ebD1C94C4be51c43'
+# Produces blocks on-demand
+NoNewHeadsThreshold = '0'
+OCR.ContractConfirmations = 1
+LogPollInterval = '10s'
+
+[GasEstimator]
+Mode = 'Arbitrum'
+LimitMax = 1_000_000_000
+# Arbitrum-based chains uses the suggested gas price, so we don't want to place any limits on the minimum
+PriceMin = '0'
+PriceDefault = '0.1 gwei'
+FeeCapDefault = '1000 gwei'
+BumpThreshold = 5