fix: use testify instead of t.Fatal or t.Error in etcdctl packages

[mmorel-35]

Description

This uses testify instead of testing for t.Fatal or t.Error calls in client package

Related to #18972

[k8s-ci-robot]

Hi @mmorel-35. Thanks for your PR.

I'm waiting for a etcd-io member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 68.71%. Comparing base (25dfc82) to head (3b8b0b4).
Report is 7 commits behind head on main.

Additional details and impacted files

see 18 files with indirect coverage changes

@@            Coverage Diff             @@
##             main   #18969      +/-   ##
==========================================
- Coverage   68.83%   68.71%   -0.12%     
==========================================
  Files         420      420              
  Lines       35626    35626              
==========================================
- Hits        24523    24482      -41     
- Misses       9679     9713      +34     
- Partials     1424     1431       +7     

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[ahrtr]

/ok-to-test

[mmorel-35]

/test pull-etcd-integration-1-cpu-arm64

[mmorel-35]

/retest

[jmhbnz]

LGTM - Thanks @mmorel-35

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: ahrtr, jmhbnz, mmorel-35

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• OWNERS [ahrtr,jmhbnz]

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