feat: lower some IGP quotes (#5347)

### Description

- Base and OP cut in half
- Lower the ethereum gas price

### Drive-by changes

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Are there any minor or drive-by changes also included?
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### Related issues

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- Fixes #[issue number here]
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### Backward compatibility

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Are these changes backward compatible? Are there any infrastructure
implications, e.g. changes that would prohibit deploying older commits
using this infra tooling?

Yes/No
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### Testing

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What kind of testing have these changes undergone?

None/Manual/Unit Tests
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rust/sealevel/environments/mainnet3/gas-oracle-configs.json

@@ -19,7 +19,7 @@
     "base": {
       "oracleConfig": {
         "tokenExchangeRate": "203047922474445771936",
-        "gasPrice": "502398873",
+        "gasPrice": "251199323",
         "tokenDecimals": 18
       },
       "overhead": 166887
@@ -67,7 +67,7 @@
     "optimism": {
       "oracleConfig": {
         "tokenExchangeRate": "203047922474445771936",
-        "gasPrice": "502398873",
+        "gasPrice": "251199323",
         "tokenDecimals": 18
       },
       "overhead": 166887

typescript/infra/config/environments/mainnet3/gasPrices.json

@@ -140,7 +140,7 @@
     "decimals": 9
   },
   "ethereum": {
-    "amount": "20.047740244",
+    "amount": "10",
     "decimals": 9
   },
   "everclear": {

typescript/infra/src/config/gas-oracle.ts

@@ -171,15 +171,15 @@ function getMinUsdCost(local: ChainName, remote: ChainName): number {
     // aren't accounted for directly in the gas price.
     arbitrum: 0.5,
     ancient8: 0.5,
-    base: 0.5,
+    base: 0.25,
     blast: 0.5,
     bob: 0.5,
     fraxtal: 0.5,
     linea: 0.5,
     mantapacific: 0.5,
     mantle: 0.5,
     mode: 0.5,
-    optimism: 0.5,
+    optimism: 0.25,
     polygonzkevm: 0.5,
     // Scroll is more expensive than the rest due to higher L1 fees
     scroll: 1.5,