elbv2: Fix attribute key not recognized

[YakDriver]

Community Note

• Please vote on this pull request by adding a 👍 reaction to the original pull request comment to help the community and maintainers prioritize this request
• Please do not leave "+1" or other comments that do not add relevant new information or questions, they generate extra noise for pull request followers and do not help prioritize the request

Closes #23971
Relates #18593
Relates #14764

Output from acceptance testing:

% make testacc TESTS=TestAccELBV2LoadBalancer PKG=elbv2
==> Checking that code complies with gofmt requirements...
TF_ACC=1 go test ./internal/service/elbv2/... -v -count 1 -parallel 20 -run='TestAccELBV2LoadBalancer'  -timeout 180m
--- SKIP: TestAccELBV2LoadBalancer_ALB_outpost (1.48s)
--- PASS: TestAccELBV2LoadBalancer_networkLoadBalancerEIP (228.30s)
--- SKIP: TestAccELBV2LoadBalancerDataSource_outpost (0.46s)
--- PASS: TestAccELBV2LoadBalancer_NLB_basic (239.67s)
--- PASS: TestAccELBV2LoadBalancer_NetworkLoadBalancerSubnet_change (239.73s)
--- PASS: TestAccELBV2LoadBalancer_NLB_privateIPv4Address (242.69s)
--- PASS: TestAccELBV2LoadBalancer_backwardsCompatibility (243.26s)
--- PASS: TestAccELBV2LoadBalancer_noSecurityGroup (250.89s)
--- PASS: TestAccELBV2LoadBalancer_generatedName (250.99s)
--- PASS: TestAccELBV2LoadBalancer_ALB_basic (251.37s)
--- PASS: TestAccELBV2LoadBalancer_namePrefix (253.70s)
--- PASS: TestAccELBV2LoadBalancerDataSource_basic (255.12s)
--- PASS: TestAccELBV2LoadBalancerDataSource_backwardsCompatibility (262.18s)
--- PASS: TestAccELBV2LoadBalancer_generatesNameForZeroValue (287.20s)
--- PASS: TestAccELBV2LoadBalancer_NLBAccessLogs_prefix (332.46s)
--- PASS: TestAccELBV2LoadBalancer_ALBAccessLogs_prefix (335.70s)
--- PASS: TestAccELBV2LoadBalancer_ApplicationLoadBalancer_updateWafFailOpen (339.18s)
--- PASS: TestAccELBV2LoadBalancer_LoadBalancerType_gateway (101.18s)
--- PASS: TestAccELBV2LoadBalancer_NetworkLoadBalancer_updateCrossZone (358.49s)
--- PASS: TestAccELBV2LoadBalancer_tags (365.42s)
--- PASS: TestAccELBV2LoadBalancer_ALB_accessLogs (385.66s)
--- PASS: TestAccELBV2LoadBalancer_NLB_accessLogs (391.74s)
--- PASS: TestAccELBV2LoadBalancer_updateDesyncMitigationMode (393.65s)
--- PASS: TestAccELBV2LoadBalancer_LoadBalancerTypeGateway_enableCrossZoneLoadBalancing (145.42s)
--- PASS: TestAccELBV2LoadBalancer_ipv6SubnetMapping (211.25s)
--- PASS: TestAccELBV2LoadBalancer_updatedSecurityGroups (274.18s)
--- PASS: TestAccELBV2LoadBalancer_updatedIPAddressType (300.97s)
--- PASS: TestAccELBV2LoadBalancer_updatedSubnets (298.76s)
--- PASS: TestAccELBV2LoadBalancer_ApplicationLoadBalancer_updateDeletionProtection (309.66s)
--- PASS: TestAccELBV2LoadBalancer_ApplicationLoadBalancer_updateHTTP2 (304.03s)
--- PASS: TestAccELBV2LoadBalancer_ApplicationLoadBalancer_updateDropInvalidHeaderFields (331.98s)
PASS
ok  	github.com/hashicorp/terraform-provider-aws/internal/service/elbv2	573.166s

[ewbankkit]

LGTM 🚀.

[github-actions]

This functionality has been released in v4.9.0 of the Terraform AWS Provider. Please see the Terraform documentation on provider versioning or reach out if you need any assistance upgrading.

For further feature requests or bug reports with this functionality, please create a new GitHub issue following the template. Thank you!

[github-actions]

I'm going to lock this pull request because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active issues.
If you have found a problem that seems related to this change, please open a new issue and complete the issue template so we can capture all the details necessary to investigate further.