d/aws_elbv2_listener_rule(test): fix flaky test configuration (hashic…

…orp#40142)

This change prevents intermittent panics caused by variable lengths of the random integer appended to the generated resource name. This approach now mirrors how the corresponding resoure acceptance test handles truncating the generated resource name.

```console
% make testacc PKG=elbv2 TESTS=TestAccELBV2ListenerRuleDataSource_actionForwardWeightedStickiness
make: Verifying source code with gofmt...
==> Checking that code complies with gofmt requirements...
TF_ACC=1 go1.23.2 test ./internal/service/elbv2/... -v -count 1 -parallel 20 -run='TestAccELBV2ListenerRuleDataSource_actionForwardWeightedStickiness'  -timeout 360m
2024/11/15 09:31:54 Initializing Terraform AWS Provider...

--- PASS: TestAccELBV2ListenerRuleDataSource_actionForwardWeightedStickiness (237.37s)
PASS
ok      github.com/hashicorp/terraform-provider-aws/internal/service/elbv2      243.811s
```

internal/service/elbv2/listener_rule_data_source_test.go

@@ -432,6 +432,7 @@ func TestAccELBV2ListenerRuleDataSource_actionForwardWeightedStickiness(t *testi
 
 	var listenerRule awstypes.Rule
 	rName := sdkacctest.RandomWithPrefix(acctest.ResourcePrefix)
+	rName = rName[:min(len(rName), 30)]
 	dataSourceName := "data.aws_lb_listener_rule.test"
 	resourceName := "aws_lb_listener_rule.test"
 
@@ -1106,7 +1107,7 @@ resource "aws_security_group" "test" {
     cidr_blocks = ["0.0.0.0/0"]
   }
 }
-`, rName[:30]))
+`, rName))
 }
 
 func testAccListenerRuleDataSourceConfig_actionRedirect(rName string) string {