Add ODB network ARN route target support

[OzakiRoy]

Description

Adds support for odb_network_arn as an EC2 route target.

This follows the existing route target implementation pattern used by route targets such as core_network_arn.

This PR adds odb_network_arn support to:

• aws_route
• aws_route data source
• inline route blocks in aws_route_table

Relations

Closes #44672

Output from Acceptance Testing

% go test ./internal/service/ec2 -run '^$'
ok      github.com/hashicorp/terraform-provider-aws/internal/service/ec2        (cached) [no tests to run]

Acceptance tests requiring real ODB Network resources were not run.

[github-actions]

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