[2.26.x] Removed CMSClassUnloadingEnabled flag from Jenksfile

[jlcsmith]

What does this PR do?

Removed CMSClassUnloadingEnabled from the maven options. This doesn't appear to be needed and is causing issues with downstream projects.

Who is reviewing it?

@rececoffin @derekwilhelm

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@codice/build

Ask 2 committers to review/merge the PR and tag them here.

@rececoffin @derekwilhelm

How should this be tested?

Successful CI build

Any background context you want to provide?

What are the relevant tickets?

Fixes: #____

Screenshots

Checklist:

• [ ] Documentation Updated
• [ ] Update / Add Threat Dragon models
• [ ] Update / Add Unit Tests
• [ ] Update / Add Integration Tests

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[jlcsmith]

build now

[cxddfbot]

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[cxddfbot]

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