zwe support messages update

[Martin-Zeithaml]

• Forgotten undefined message updated:

common.printErrorAndExit(`Error ZWELxxxx: "${targetDirectory}" is not a valid directory.`, undefined, 999);

• Few minor updates to reduce number of issues found by zwe_message_checks

Quick test

• --target-dir is a file

$: /zowe/bin/zwe support -c ./yaml/zowe.basic.yaml --target-dir ./zowe.env
===============================================================================
>> COLLECT INFORMATION FOR ZOWE SUPPORT

ERROR: Error ZWEL0321E: /qa/support/zowe.env is not a valid directory.

• --target-dir is a special file

$: /zowe/bin/zwe support -c ./yaml/zowe.basic.yaml --target-dir /dev/null
===============================================================================
>> COLLECT INFORMATION FOR ZOWE SUPPORT

ERROR: Error ZWEL0321E: /dev/null is not a valid directory.

[github-actions]

build 7046 SUCCEEDED.
Link to workflow run: https://github.com/zowe/zowe-install-packaging/actions/runs/13407911952

[github-actions]

Test workflow 6147 is started.
Running install test: Convenience Pax
The zowe artifact being used by this test workflow: libs-snapshot-local/org/zowe/3.2.0-PR-4201/zowe-3.2.0-pr-4201-7046-20250219080822.pax
Running on machine: zzow09
Result: FAILURE
Link to workflow run: https://github.com/zowe/zowe-install-packaging/actions/runs/13408025356

[1000TurquoisePogs]

Can you please change it to ID 322?
#4200 contains 321.

[github-actions]

build 7057 SUCCEEDED.
Link to workflow run: https://github.com/zowe/zowe-install-packaging/actions/runs/13442954117

[github-actions]

Test workflow 6159 is started.
Running install test: Convenience Pax
The zowe artifact being used by this test workflow: libs-snapshot-local/org/zowe/3.2.0-PR-4201/zowe-3.2.0-pr-4201-7057-20250220192204.pax
Running on machine: zzow10
Result: FAILURE
Link to workflow run: https://github.com/zowe/zowe-install-packaging/actions/runs/13443062396