Disable dynamic config updates for stress test server (RTC issue 302196)

[tjwatson]

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• If this PR fixes an Issue, the description includes "Fixes #FILLMEIN" or "Resolves #FILLMEIN" (verify release bug label if applicable: https://github.com/OpenLiberty/open-liberty/wiki/Open-Liberty-Conventions).
• If this PR resolves an external Known Issue (including APARS), the description includes "Fixes #FILLMEIN" or "Resolves #FILLMEIN".

[tjwatson]

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[tjwatson]

!build (view Open Liberty Personal Build - ✅ completed successfully!)

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[LibbyBot]

Code analysis and actions

DO NOT DELETE THIS COMMENT.

• 1 FAT files were changed, added, or removed.

• Check that the build did not break the affected FAT suite(s).

• Please describe in a separate comment how you tested your changes.

[LibbyBot]

Code analysis and actions

DO NOT DELETE THIS COMMENT.

• 1 FAT files were changed, added, or removed.

• Check that the build did not break the affected FAT suite(s).

• Please describe in a separate comment how you tested your changes.

[tbitonti]

This fixes WS-CD RTC defect 302196.
"est Failure: com.ibm.ws.microprofile.config.fat.tests.StressTest.StressTestServlet.testLargeConfigSources_EE8_FEATURES_MicroProfile_33".