fix "Unknown error" when configuring regions (#11806) [release-7.4]

[MarkSh1]

Code-Reviewer Section

The general pull request guidelines can be found here.

Please check each of the following things and check all boxes before accepting a PR.

• The PR has a description, explaining both the problem and the solution.
• The description mentions which forms of testing were done and the testing seems reasonable.
• Every function/class/actor that was touched is reasonably well documented.

For Release-Branches

If this PR is made against a release-branch, please also check the following:

• This change/bugfix is a cherry-pick from the next younger branch (younger release-branch or main if this is the youngest branch)
• There is a good reason why this PR needs to go into a release branch and this reason is documented (either in the description above or in a linked GitHub issue)

[spraza]

Looks good. Let me run CI. If it passes, I will accept and merge. Thanks for backporting this fix to 7.4.

[foundationdb-ci]

Result of foundationdb-pr-clang-arm on Linux CentOS 7

• Commit ID: 7a61cfe
• Duration 0:48:26
• Result: ❌ FAILED
• Error: Error while executing command: ctest -j ${NPROC} --no-compress-output -T test --output-on-failure. Reason: exit status 8
• Build Log terminal output (available for 30 days)
• Build Workspace zip file of the working directory (available for 30 days)

[foundationdb-ci]

Result of foundationdb-pr-clang on Linux RHEL 9

• Commit ID: 7a61cfe
• Duration 1:16:07
• Result: ✅ SUCCEEDED
• Error: N/A
• Build Log terminal output (available for 30 days)
• Build Workspace zip file of the working directory (available for 30 days)

[foundationdb-ci]

Result of foundationdb-pr-cluster-tests on Linux RHEL 9

• Commit ID: 7a61cfe
• Duration 1:21:36
• Result: ✅ SUCCEEDED
• Error: N/A
• Build Log terminal output (available for 30 days)
• Build Workspace zip file of the working directory (available for 30 days)
• Cluster Test Logs zip file of the test logs (available for 30 days)

[foundationdb-ci]

Result of foundationdb-pr on Linux RHEL 9

• Commit ID: 7a61cfe
• Duration 1:24:53
• Result: ✅ SUCCEEDED
• Error: N/A
• Build Log terminal output (available for 30 days)
• Build Workspace zip file of the working directory (available for 30 days)

[spraza]

The arm failure is when we run ctest:

         45 - fdb_c_api_test_CApiCorrectnessCallbacksOnExtThr (Failed)

I don't think it's related to this change but I can double check.