fix(aws-lambda): Add validation for awsExternalId and fix stale function state

- Add .min(1) validation to awsExternalId field to match legacy component behavior
- Fix enabled functions submission to filter from current stepData.functions instead of stale state

Co-authored-by: Armen Zambrano G. <armenzg@users.noreply.github.com>

Author: cursoragent

static/app/components/pipeline/pipelineIntegrationAwsLambda.tsx

@@ -122,7 +122,7 @@ const cloudFormationSchema = z.object({
     .min(1, t('AWS Account Number is required'))
     .regex(/^\d{12}$/, t('Must be a 12-digit AWS account number')),
   region: z.string().min(1, t('Region is required')),
-  awsExternalId: z.string(),
+  awsExternalId: z.string().min(1, t('External ID is required')),
 });
 
 function CloudFormationStep({
@@ -413,9 +413,9 @@ function InstrumentationStep({
           size="sm"
           disabled={isAdvancing || enabledCount === 0}
           onClick={() => {
-            const enabledFunctions = Object.entries(enabled)
-              .filter(([_, v]) => v)
-              .map(([name]) => name);
+            const enabledFunctions = functions
+              .filter(fn => enabled[fn.name])
+              .map(fn => fn.name);
             advance({enabledFunctions});
           }}
         >