fix: added 400 and 401/removed 500 error scenarios in .feature

[Kevsy]

What type of PR is this?

Add one of the following kinds:

• correction

What this PR does / why we need it:

1. Adds 400 and 401 error scenarios to the .feature file
2. removes the redundant 500 scenario
3. makes the other test steps consistent with the syntax in the new 400 and 401 scenarios

Which issue(s) this PR fixes:

Fixes #134, #135

Special notes for reviewers:

Changelog input

 release-note

Additional documentation

This section can be blank.

docs

[github-actions]

🦙 MegaLinter status: ✅ SUCCESS

Descriptor	Linter	Files	Fixed	Errors	Elapsed time
✅ ACTION	actionlint	2		0	0.01s
✅ API	spectral	1		0	1.52s
✅ GHERKIN	gherkin-lint	1		0	0.32s
✅ REPOSITORY	git_diff	yes		no	0.01s
✅ REPOSITORY	secretlint	yes		no	0.61s
✅ YAML	yamllint	1		0	0.4s

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[Kevsy]

@maheshc01 please may I ask for your urgent review? The PR adds 400 and 401 error scenarios, removes the unwanted 500 scenario, and updates the other scenarios so that all the outcomes (the 'Then' steps) are consistent.

[maheshc01]

looks good.