Feature spec for squash option edge cases mentioned in part 2

Issue #17613 (closed)

MR	Changes
Part 1 > !33099 (merged)	BE implementation
Part 2 > !33827 (merged)	FE implementation of squash option and MR form
Part 3 > !34891 (merged)	FE implementation of squash option in MR widget
Part 4 > !35081 (merged)	FE implementation of squash option tooltip
Part 5 > !35111 (merged)	FE implementation of squash option message in MR form
👉 Part 6 (current)	Additional spec for testing edge case for part 2
Docs > !33930 (merged)	Documentation

What does this MR do?

Add feature spec for testing "Required" and "Do not allow scenario:

• !33827 (comment 370380742)
• !33827 (comment 368555220)

Required

Recovers what is saved last (The "Required" state can be saved and will override the original MR state)

1. Existing MR is unchecked
2. Maintainer changes it to "Required" (checked)
3. Go to edit MR, which is disabled and checked. Clicks "save".
4. Maintainer changes it to be "Allow" (unchecked)
5. Go to edit MR, squash commit will recover the latest saved state (which the project setting has overridden the MR setting), and displays checked

Do not allow

Recovers MR state (The "Do not allow" is never saved)

1. Existing MR has checked
2. Maintainer changes it to "Do not allow" (unchecked)
3. Go to edit MR, there is no squash option. Clicks "save".
4. Maintainer changes it to be "Allow" (uncheck)
5. Go to edit MR, squash commit will recover the MR state and displays checked

Screenshots

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team

Closes #17613 (closed)