Revert "Bump org.jenkins-ci.plugins:ssh-credentials in /bom-weekly (#3402)" (#3404)

Plugin loading fails in several BOM tests, including:

* `LINE=2.440.x PLUGINS=git-server TEST=InjectedTest bash local-test.sh`

https://ci.jenkins.io/job/Tools/job/bom/view/change-requests/job/PR-3374/10/testReport/
lists the other plugins with failures as:

* workflow-basic-steps with 2.440.x
* git with 2.440.x and 2.452.x
* pipeline-model-definition with 2.452.x
* docker-workflow with 2.440.x and 2.452.x
* blueocean plugin with 2.440.x and 2.452.x

This reverts commit 63a6418.

Author: MarkEWaite

bom-weekly/pom.xml

@@ -984,7 +984,7 @@
       <dependency>
         <groupId>org.jenkins-ci.plugins</groupId>
         <artifactId>ssh-credentials</artifactId>
-        <version>342.ve5a_f1db_5a_132</version>
+        <version>337.v395d2403ccd4</version>
       </dependency>
       <dependency>
         <groupId>org.jenkins-ci.plugins</groupId>