Deprecate /transaction-confirmation endpoint (#1973)

Adds swap and staking test coverage to the `/preview` endpoint to ensure usage of it can replace the `/transaction-confirmation` one (migrated from the latter's suite), fixing any found issues:

- Decode staking transaction data instead of using `dataDecoded` (because of batches).
- Correct types for `/preview` endpoint.
- Add swap/staking test coverage to `/preview` endpoint.
- Update other tests according.

src/config/entities/__tests__/configuration.ts

@@ -218,7 +218,7 @@ export default (): ReturnType<typeof configuration> => ({
       42161: faker.internet.url({ appendSlash: false }),
       11155111: faker.internet.url({ appendSlash: false }),
     },
-    explorerBaseUri: faker.internet.url(),
+    explorerBaseUri: faker.internet.url({ appendSlash: true }),
     restrictApps: false,
     allowedApps: [],
     maxNumberOfParts: faker.number.int(),

src/domain/staking/contracts/decoders/kiln-decoder.helper.ts

@@ -29,6 +29,8 @@ export class KilnDecoder extends AbiDecoder<typeof KilnAbi> {
     super(KilnAbi);
   }
 
+  // TODO: When confirmation view endpoint is removed, remove this
+  // and use this.helpers.isDeposit instead
   decodeDeposit(
     data: `0x${string}`,
   ): { method: string; parameters: [] } | null {
@@ -50,6 +52,8 @@ export class KilnDecoder extends AbiDecoder<typeof KilnAbi> {
     }
   }
 
+  // TODO: When confirmation view endpoint is removed, return only
+  // publicKeys and don't format it like DataDecoded
   decodeValidatorsExit(data: `0x${string}`): {
     method: string;
     parameters: KilnRequestValidatorsExitParameters[];
@@ -79,6 +83,8 @@ export class KilnDecoder extends AbiDecoder<typeof KilnAbi> {
     }
   }
 
+  // TODO: When confirmation view endpoint is removed, return only
+  // publicKeys and don't format it like DataDecoded
   decodeBatchWithdrawCLFee(data: `0x${string}`): {
     method: string;
     parameters: KilnBatchWithdrawCLFeeParameters[];