Use stored value of method instead of calling same method again.

Description

$block->getPartners() is stored in variable name $partners. So it should use the variable value instead of calling $block->getPartners() again.

Fixed Issues (if relevant)

N/A

Manual testing scenarios

1. Check the currency drop-down in frontend part.

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)
• All automated tests passed successfully (all builds on Travis CI are green)