fix(dhl): use getGatewayURL() for sandbox mode support in XML quotes

[lbajsarowicz]

Description

Replace hardcoded gateway_xml_url config with getGatewayURL() method call in _getQuotes().

The getGatewayURL() method correctly handles sandbox mode by checking sandbox_mode config and returning the appropriate URL:

• Production: gateway_xml_url
• Sandbox: sandbox_xml_url

Root cause: Line 1092 in _getQuotes() used $this->getConfigData('gateway_xml_url') directly, bypassing the sandbox mode logic in getGatewayURL().

Related Pull Requests

None

Fixed Issues (if relevant)

1. Fixes Sandbox mode does not work for DHL (XML) #40249

Manual testing scenarios

1. Enable DHL shipping method in Admin > Stores > Configuration > Sales > Shipping Methods > DHL
2. Enable Sandbox Mode and configure sandbox credentials
3. Add a product to cart and proceed to checkout
4. Enter shipping address and request shipping rates
5. Before fix: DHL returns "Validation Failure: Site Id is wrong" (production URL used with sandbox credentials)
6. After fix: DHL returns valid shipping rates from sandbox environment

Questions or comments

The getGatewayURL() method already exists and handles sandbox mode correctly for other DHL operations. This fix ensures _getQuotes() uses the same logic.

Contribution checklist

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/integration tests (if applicable)
• README.md files for modified modules are updated and included in the pull request if any README.md predefined sections require an update
• All automated tests passed successfully (all builds are green)

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[lbajsarowicz]

@magento run all tests

[lbajsarowicz]

@magento run Functional Tests B2B, Functional Tests EE, Functional Tests CE