feat: Add credential test with DNS retry logic

[DannyLiCom]

Fixes / Features

• Add credential test with DNS retry logic
• Added a run_command_and_capture_output function to capture errors

Testing / Documentation

To verify this feature, run the standard xpk cluster create-pathways command. The new credential test with DNS retry logic will be executed as part of the cluster creation process.
https://screenshot.googleplex.com/cTjV7ABQr2omQZd

If a DNS endpoint-related error occurs, the following message will be displayed, followed by an automatic retry:
https://screenshot.googleplex.com/BunMupVA8Yp998o
However, because the --enable-dns-access flag is present by default, the error mentioned above will not appear.

• [ y/n ] Tests pass
• [ y/n ] Appropriate changes to documentation are included in the PR

[DannyLiCom]

@SujeethJinesh Please review this PR. My current default for get-credentials is --dns-endpoint, because I see that the create cluster command also defaults to --enable-dns-access.

[DannyLiCom]

@scaliby I modified the if statements to reduce nesting. Please review it again.

[SujeethJinesh]

This looks good to me, just needed confirmation about --force-conflicts

[scaliby]

@DannyLiCom any updates on this?

[DannyLiCom]

@DannyLiCom any updates on this?

@scaliby The check below is showing the error "Kubernetes cluster can't find Job." I don't think this is related to my get_credential modifications, and I'm not sure what to change to fix it.
https://screenshot.googleplex.com/4Qs6co5Tv4FGku9

[DannyLiCom]

@jamOne- If there are no issues, can you help me merge it? It seems authorization is required to merge now.

[DannyLiCom]

@jamOne- The check is getting stuck at the verify goldens and appears to be blocked by a "No module named 'ruamel'" error.

[jamOne-]

ruamel is one of our dependencies, please install them with pip install -e .

[DannyLiCom]

@jamOne- Please review it again! Thanks!