Use null coalesce operator instead of ternary operator.

Problem/Motivation

FILE: ...al9/web/modules/contrib/partner_link/src/Plugin/Block/PartnerLinkBlock.php
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FOUND 2 ERRORS AFFECTING 2 LINES
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 115 | ERROR |  Use null coalesce operator instead of ternary operator.
 121 | ERROR |  Use null coalesce operator instead of ternary operator.
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Time: 2.23 secs; Memory: 10MB