fix: force LANG=C on MQ 10.0 container to fix JmsReplyToIbmMQTest

[gnodet]

Summary

Fix the JmsReplyToIbmMQTest.testCustomJMSReplyToInOut test failure introduced by the IBM MQ 10.0 upgrade in PR #25107.

• IBM MQ 10.0 changed the default locale from C to C.utf8, causing the queue manager to use CCSID 1208 (UTF-8) instead of CCSID 819 (ISO 8859-1)
• This change causes the JMS reply-to mechanism to fail silently — the reply message never reaches DEV.QUEUE.2
• Force LANG=C on the container to preserve the CCSID 819 behavior from MQ 9.4.x

This is a pragmatic fix to validate the CCSID hypothesis. If CI passes with this change, the CCSID locale change is confirmed as the root cause. A proper fix (supporting CCSID 1208 natively) can be investigated as a follow-up.

Test plan

• JmsReplyToIbmMQTest.testCustomJMSReplyToInOut should pass (currently fails 3/3 runs)
• JmsComponentIbmMQTest.testSend should continue to pass
• No regressions in other JMS tests

Claude Code on behalf of gnodet

[github-actions]

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[gnodet]

Closing: PR targeting a feature branch doesn't trigger the main build. Will re-create targeting main.