[PHP 7.4] implode() parameter order

Problem/Motivation

Checking for PHP 7.4 compatibility yields this:

FILE: elysia_cron.drush.inc
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FOUND 0 ERRORS AND 1 WARNING AFFECTING 1 LINE
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 131 | WARNING | Passing the $glue and $pieces parameters in reverse order to implode has been deprecated since PHP 7.4; $glue should be the first parameter and $pieces the
     |         | second
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Steps to reproduce

Proposed resolution

Update code to use correct param order.

Remaining tasks

User interface changes

None

API changes

None

Data model changes

None