#2734 fix(conformance): batch E services to 100% on the refreshed models

Summary

Fixes every variant still failing on main outside the open PRs (apigatewayv2, bedrock, cloudfront, ecs, glue, monitoring, sqs).

• apigatewayv2: product REST endpoint pages store TryItState. Product page / REST endpoint page updates are partial (omitted members keep their stored values) and return NotFoundException for a missing page instead of creating it. The existence check and the write share one lock, so an update can't bring back a page deleted at the same moment.
• bedrock: the GET router keeps interior empty path segments, so an empty interior label (e.g. /automated-reasoning-policies//build-workflows/...) reaches its op and gets ValidationException instead of a 501. Trailing-slash -> List routing (#1645) is unchanged.
• ecs capacity providers:
  • A provider needs exactly one backing (Auto Scaling group or Managed Instances config).
  • Managed Instances providers are cluster-scoped. They are listed when you pass cluster, by name or ARN, and Update/Delete honor cluster.
  • FARGATE/FARGATE_SPOT are listed after your own providers.
  • maxResults/nextToken paging works, responses never emit nulls, and the reserved-prefix check is case-insensitive.
  • CloudFormation stores the API's camelCase shape, applies the same backing rule, and keeps ClusterName only for Managed Instances providers (resolved from a name or an ARN).
• glue: DeleteIntegration returns only its output members.
• cloudwatch: PutLogAlarm accepts an empty QueryString, which the model allows.
• probe:
  • negative_too_short is skipped only when the empty value is the final URI label and the shortened request is byte-identical to another op in the same model: same method, same path, same query literals. That request is the other op on the wire, and SDKs refuse empty labels client-side. The rule is derived from the model and unit-tested.
  • The XML validator honors member xmlName for flattened lists. An absent flattened list counts as empty, which fixes the SQS DeleteMessageBatch false failure.

Variant totals drop by 99 repo-wide from the skip (iot 27, appsync 12, transcribe 9, bedrock 7, s3 7, others smaller). Baseline and doc counts are regenerated in the final re-baseline batch.

Test plan

• cargo fmt --check, cargo clippy --workspace --all-targets -D warnings
• lib: conformance, ecs, cloudformation, apigatewayv2, bedrock, glue, cloudwatch, sqs
• conformance tests: ecs, apigatewayv2, s3, bedrock, cloudfront, glue, cloudwatch, sqs
• e2e: ecs, cloudformation_ecs, apigatewayv2, bedrock, glue, cloudwatch, sqs
• probe 100%: apigatewayv2 2786, bedrock 4037, cloudfront 4110, ecs 2442, glue 10478, monitoring 1909, sqs 541, s3 4061

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Summary by cubic

Fixes the remaining conformance failures on the refreshed models across apigatewayv2, bedrock, ecs, glue, cloudwatch, and sqs. Product page updates are now partial and return NotFoundException for a missing page, REST endpoint pages store TryItState, bedrock GET keeps interior empty path segments, DeleteIntegration omits IntegrationConfig, and PutLogAlarm accepts an empty QueryString.

ECS capacity providers

• A provider needs exactly one backing: Auto Scaling group or Managed Instances; the reserved-prefix check is case-insensitive.
• Managed Instances providers are cluster-scoped by name or ARN; Update/Delete must name their own cluster, and FARGATE/FARGATE_SPOT are listed after your own providers.
• maxResults/nextToken paging works and responses never emit nulls.
• CloudFormation stores the API's camelCase shape and applies the same backing and cluster rules.

Conformance probe fixes

• negative_too_short is skipped only when an empty trailing label collapses the request onto a byte-identical same-method operation.
• The XML validator honors member xmlName and treats an absent flattened list as empty, fixing the SQS DeleteMessageBatch false failure.